chore(repo): Update dependency svgo@>=3.0.0 <3.3.3 to v4 [SECURITY] - #9572

Details

Summary

SVGO accepts XML with custom entities, without guards against entity expansion or recursion. This can result in a small XML file (811 bytes) stalling the application and even crashing the Node.js process with JavaScript heap out of memory.

Details

The upstream XML parser (sax) doesn't interpret custom XML entities by default. We pattern matched custom XML entities from the DOCTYPE, inserting them into parser.ENTITIES, and enabled unparsedEntities. This gives us the desired behavior of supporting SVGs with entities declared in the DOCTYPE.

However, entities can reference other entities, which can enable small SVGs to explode exponentially when we try to parse them.

Proof of Concept

import { optimize } from 'svgo';

/** Presume that this string was obtained in some other way, such as network. */
const original = `
  <?xml version="1.0"?>
  <!DOCTYPE lolz [
  <!ENTITY lol "lol">
  <!ELEMENT lolz (#PCDATA)>
  <!ENTITY lol1 "&lol;&lol;&lol;&lol;&lol;&lol;&lol;&lol;&lol;&lol;">
  <!ENTITY lol2 "&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;">
  <!ENTITY lol3 "&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;">
  <!ENTITY lol4 "&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;">
  <!ENTITY lol5 "&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;">
  <!ENTITY lol6 "&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;">
  <!ENTITY lol7 "&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;">
  <!ENTITY lol8 "&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;">
  <!ENTITY lol9 "&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;">
  ]>
  <lolz>&lol9;</lolz>
`;

optimize(original);

Impact

If SVGO is run on untrusted input (i.e., user uploaded to server-side application), then the untrusted SVG can effectively stall or crash the application with an SVG < 1 KB in size.

It's unlikely to impact users who just use SVGO locally on their own SVGs or in build pipelines.

Patches

SVGO has patched v4.0.1, v3.3.3, and v2.8.1! However, it's strongly recommended to upgrade to v4 regardless, as previous versions are not officially supported anymore.

Workarounds

== 4.0.0

For v4, users do not specifically have to upgrade SVGO, though it is recommended to do so. A package manager can be used to upgrade sax recursively:

For example:

yarn up -R sax

New options were introduced upstream which makes the way SVGO parses SVGs safe by default.

>= 2.1.0, <= 3.3.2

Users of v3 and v2 will have to take manual action. If users can't upgrade, they may be able to work around this as long as the project doesn't require support for custom XML entities, though it's not a simple flag.

Parse the DOCTYPE directly and check for the presence of custom entities. If entities are present, throw/escape before passing them to SVGO.

+ import SAX from 'sax';
  import { optimize } from 'svgo';

- const original =`
+ let original = `
    <?xml version="1.0"?>
    <!DOCTYPE lolz [
    <!ENTITY lol "lol">
    <!ELEMENT lolz (#PCDATA)>
    <!ENTITY lol1 "&lol;&lol;&lol;&lol;&lol;&lol;&lol;&lol;&lol;&lol;">
    <!ENTITY lol2 "&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;">
    <!ENTITY lol3 "&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;">
    <!ENTITY lol4 "&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;">
    <!ENTITY lol5 "&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;">
    <!ENTITY lol6 "&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;">
    <!ENTITY lol7 "&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;">
    <!ENTITY lol8 "&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;">
    <!ENTITY lol9 "&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;">
    ]>
    <lolz>&lol9;</lolz>
  `;

+ const parser = SAX.parser();
+ /** @param {string} doctype */
+ parser.ondoctype = (doctype) => {
+   original = original.replace(doctype, '');
+ }
+ parser.write(original);

  optimize(original);

Resources

• Wikipedia: Billion laughs attack

Severity

• CVSS Score: 7.5 / 10 (High)
• Vector String: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References

• https://github.com/svg/svgo/security/advisories/GHSA-xpqw-6gx7-v673
• https://nvd.nist.gov/vuln/detail/CVE-2026-29074
• https://github.com/advisories/GHSA-xpqw-6gx7-v673

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

Details

Summary

SVGO's removeScripts plugin (disabled by default) removes scripts from the SVG, however executable scripts were left intact in some cases. If a consumer relied on this plugin for sanitization and served them to users, these SVGs could open up doors to XSS.

Details

SVGO has a plugin for removing scripts from an SVG, which removes:

• <script> elements
• JavaScript URIs (v4 and v3 only)
• on… event handlers (v4 and v3 only)

While SVGO is not a sanitization library, SVGO continues to maintain the plugin for those already using it for this purpose.

However, there were two problems:

• SVGO did not check namespaced/prefixed script elements, for example if one declared an explicit prefix for the SVG namespace ( <svg:script>) instead of using the default namespace ( <script>), the <svg:script> tag would be left intact.
• SVGO case sensitively matched JavaScript URIs, but it should've been case-insensitive.

Proof of Concept

import { optimize } from 'svgo';

/** Presume that this string was obtained in some other way, such as network. */
const original = `
  <svg xmlns="http://www.w3.org/2000/svg" xmlns:svg="http://www.w3.org/2000/svg" xmlns:uwu="http://www.w3.org/1999/xlink" viewBox="0 0 100 100" version="1.1">
    <a uwu:href="JavaScript:(() =&gt; { alert(document.cookie) })();"><text y="30">uwu</text></a>
    <svg:script>
      alert(document.cookie);
    </svg:script>
  </svg>
`;

optimize(original, {
  plugins: ['removeScripts']
});
// Did not remove <svg:script> or uwu:href="JavaScript:…—still executed by browsers.

Impact

If you run SVGO on untrusted input (e.g., user uploads to a web application) and you depended on removeScripts, then some scripts may still be present. If that SVG was then opened directly by another user on the same domain, it could invoke scripts that could read local storage or cookies.

This may affect you if you have enabled one of the following:

It's unlikely to impact users who just use SVGO locally on their own SVGs or in build pipelines.

Patches

>= 3.0.0, <= 4.0.1

SVGO patched v4.0.2 and v3.3.4. Just upgrade the dependency using your preferred package manager! For example:

yarn up svgo

##### or if SVGO is a nested dependency
yarn up -R svgo

The proposed fix is to improve our namespace-aware handling to explicitly act on the default namespace, SVG namespace, and XHTML namespace only. This handles all scripts that are executed by browsers, but will leave intact custom prefixes that happen to have an element called <*:script> which clients shouldn't treat as executable.

>= 2.0.0, <= 2.8.2

SVGO patched v2.8.3, however SVGO v2 explicitly only implements and documents that it will remove <script> elements and nothing more. It has the namespace aware handling for tags like <svg:script> or <xhtml:script>, but has not been updated to remove JavaScript URIs or event handlers like >= v3. If this is something you need, please upgrade to v4 or v3, or reach for one of the documented workarounds at the end.

>= 1.0.0, <= 1.3.2

SVGO v1 has been deprecated for a while now and won't be patched. Please upgrade to a more recent version! If something is preventing you from doing so, please reach out! We're happy to expand our migration guides or support you if you're having trouble.

Workarounds

If your motivation for enabling the plugin is SVG sanitization, consider reaching for a dedicated SVG sanitization tool and invoke it before passing the SVG to SVGO.

Severity

• CVSS Score: 8.2 / 10 (High)
• Vector String: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:L/A:N

References

• https://github.com/svg/svgo/security/advisories/GHSA-2p49-hgcm-8545
• https://github.com/svg/svgo/commit/628e3bc7336625a30365d0a9b60185307d852466
• https://github.com/svg/svgo/commit/72a23886b4698b27624b936f3a15a80afd36d75f
• https://github.com/svg/svgo/commit/f529cfccc6c154d6f6eabe276ec637a8c5db6763
• https://github.com/svg/svgo/releases/tag/v2.8.3
• https://github.com/svg/svgo/releases/tag/v3.3.4
• https://github.com/svg/svgo/releases/tag/v4.0.2
• https://github.com/advisories/GHSA-2p49-hgcm-8545

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

v4.0.2

Compare Source

What's Changed

Security

• removeScripts, remove JavaScript URIs case-insensitively and make <script> handling namespace aware. By @​SethFalco

Bug Fixes

• convertColors, skip case-normalization for CSS custom properties. By @​SethFalco in #​2213
• convertPathData, improve handling of consecutive t commands. By @​KTibow in #​2156
• convertPathData, safer handling of paths. By @​KTibow in #​2158
• Improve parsing of negative (or +) arc radii. By @​KTibow in #​2205
• When converting to a data URI, only encode it as a data URI once. By @​johnkenny54 in #​2053

Performance

• mergePaths, speed up child node removal. By @​mozzie in #​2216

Other Changes

• removeAttributesBySelector, log warning and noop if missing parameters. By @​KTibow in #​2215

v4.0.1

Compare Source

What's Changed

Dependencies

• Sets minimum version of sax (XML parser) to v1.5.0, which improves built-in guards against entity expansion.

Bug Fixes

• removeEmptyContainers, removed leftover <use> elements referencing an empty container that were removed. By @​johnkenny54 in #​2051
• removeUnknownsAndDefaults, don't remove attributes if they're referenced in attribute selectors (CSS). By @​SethFalco in #​2144

Performance

• convertPathData, refactor to reduce redundant equality checks. By @​Lorfdail in #​1764 and #​2135
• removeHiddenElems, compute styles lazily. By @​Lorfdail in #​1764 and #​2135

Other Changes

• Plugins no longer include if they are enabled or disabled by default, as this was written inconsistently. The --show-plugins argument appends the presets a plugin is in to the end of the line. By @​viralcodex in #​2174
• Plugin/preset types to enforce the name start with preset- if it is a preset (collection of plugins). By @​SethFalco in #​2178

Metrics

Before and after of the browser bundle of each respective version:

v4.0.0

Compare Source

It's been just over a year since our first release candidate, but I believe we can now release SVGO v4.0.0 with confidence! Thank you to all contributors who tested our RC builds and reported issues back up, this really smoothed out the process.

We actually wanted to do the release sooner, but it was a challenge to find the right time to publish a major release, since that means setting time aside to support users through migrations, helping downstream projects migrate, being available to fix or document things that users found to have an unexpected impact by this release, etc. I appreciate everyone's patience, and now that this is done, we can hopefully increase the pace of development again and tackle that backlog of old bugs. ^-^'

Breaking Changes

Please refer to the Migration Guide from v3 to v4 for a more concise version! This section is more verbose as it delves into the motivation of changes too.

Dropped Support for Node.js v14

Node.js v14 is no longer supported by the Node.js team, including security support, since 30 April 2023. Node.js v16 is no longer supported either, but as some are still using it, we'll save dropping support for Node.js v16 for the next major release.

This allows us to update our dependencies to more recent versions and to access more modern Node.js APIs.

Node.js v14 may still work at the time of this release, but we'll no longer be testing against v14 from now on.

Default Plugins

Both removeViewBox and removeTitle have been disabled by default. Both have been major pain points for users and don't make sense to enable in most cases. Other libraries wrapping SVGO have also been disabling these plugins by default, such as Docusaurus and SVGR.

• removeViewBox removes the scalability of SVGs.
• removeTitle reduces accessibility, which preserving accessibility is more important than optimization.

If you would like either of these plugins enabled, you can do so by configuring it in the SVGO config, see the README for more context, however please read the warnings described in the documentation of the plugins first:

  export default {
    plugins: [
      'preset-default', // built-in plugins enabled by default
+     'removeViewBox',
+     'removeTitle',
    ],
  };

removeScriptElement → removeScripts

The removeScriptElement plugin has been renamed to removeScripts, to more accurately reflect what the plugin does. It does not only remove the <script> tag, but also event handlers and script URIs from links.

To migrate, amend your SVGO config to refer to removeScripts instead if you use that plugin.

  export default {
    plugins: [
      'preset-default', // built-in plugins enabled by default
-     'removeScriptElement',
+     'removeScripts',
    ],
  };

Imports/Exports

We now enforce boundaries between the intended public API and any internal structures/helpers. This is the biggest change in SVGO's JavaScript API and will enable maintainers and users to have a mutual understanding of what is public API and what isn't.

There are two ways to import SVGO:

• svgo — for normal usage, such as scripts or server-side applications.
• svgo/browser — for browser usage.

If you use the browser bundle, you must amend how you import SVGO:

- import { optimize } from 'svgo/dist/svgo.browser.js';
+ import { optimize } from 'svgo/browser';

For ESM/browser, you must use named imports:

// ESM and Browser, named exports
import { VERSION } from 'svgo';
console.log(VERSION);  // 4.0.0-rc.0

// ESM and Browser, import all
import * as svgo from 'svgo/browser';
console.log(svgo.VERSION); // 4.0.0-rc.0

// Common JS, default export
const svgo = require('svgo');
console.log(svgo.VERSION);  // 4.0.0-rc.0

// CommonJS, named exports
const { VERSION } = require('svgo');
console.log(VERSION); // 4.0.0-rc.0

We support 3 environments, ESM, Common JS, and browser. The only functional difference is that the loadConfig function is not exported in the browser bundle.

If you depended on a helper that we haven't declared as public, then you are encouraged to implement it yourself, or dig into our source and copy it over to your project.

Importing Plugins

If you import/require the array of built-in plugins, or a single plugin during runtime, this is now a top-level export instead:

// builtin.mjs - get an array of all built-in plugins
- import { builtin } from 'svgo/lib/builtin';
+ import { builtinPlugins } from 'svgo'

// plugin.mjs - get a single plugin
- import presetDefault from 'svgo/plugins/preset-default';
+ import { builtinPlugins } from 'svgo';
+ const prefixDefault = builtinPlugins.find(plugin => plugin.name === 'preset-default');

// plugin-map.mjs - get all plugins as a map using the plugin name as a key
import { builtinPlugins } from 'svgo';
const pluginMap = builtinPlugins.reduce((acc, val) => acc.set(val.name, val), new Map());

Selector Helpers

The XastNode#parentNode property was declared legacy and pending removal for v4, but was still used internally. The remaining instances have now been removed, which required a refactor of the selector helpers.

This effects custom plugins that use any of the following functions, where the selector (2nd) argument could reference parent or sibling nodes (i.e. div > span):

• querySelectorAll
• querySelector
• matches

Previously, these functions had the context of the whole node tree, even if a child node was passed to it. It no longer has that context by default. The new API for these functions is as follows:

// applies `selector` with the context of the `childNode` and its descendants
const nodes = querySelectorAll(childNode, selector);

// applies `selector` with the context of the entire node tree relative from `childNode`
// the `rootNode` is required if the result of `selector` may depend on the parent or sibling of `childNode`
const nodes = querySelectorAll(childNode, selector, rootNode);

// this usage has the same behavior as v3, as `rootNode` is already the entire node tree 
const nodes = querySelectorAll(rootNode, selector);

A helper has been provided named #mapNodesToParents, which does this for you. This can be used to easily migrate to the new API. If you're not sure if you need it, then it's safer to take this approach. The third argument won't be necessary if selector does not traverse nodes, for example, querying using one or more attributes of a single node.

- import { querySelectorAll } from 'svgo';
+ import { querySelectorAll, mapNodesToParents } from 'svgo';

- const nodes = querySelectorAll(childNode, selector);
+ const nodes = querySelectorAll(childNode, selector, mapNodesToParents(rootNode));

What Else

ESM

SVGO is now a dual package, serving for both Common JS and ESM usage. To be more explicit, SVGO will continue to work on Common JS projects!

Thanks to @​jdufresne for doing the bulk of the work.

Default Behavior

• convertColors, now converts all references to colors excluding references to IDs to lowercase. This can be disabled by setting convertCase to false.

Bug Fixes

• cleanupIds, treat both URI encoded and non-URI encoded IDs as the same. By @​liuweifeng in #​1982
• collapseGroups, check styles as well as attributes. By @​johnkenny54 in #​1952
• collapseGroups, move attributes atomically. By @​johnkenny54 in #​1930
• convertPathData, fix q control point when item is removed. By @​KTibow in #​1927
• convertPathData, preserve vertex for markers only paths. By @​SethFalco in #​1967
• mergePaths, don't merge paths if attributes/styles depend on the node's bounding box. By @​johnkenny54 in #​1964
• moveElemsAttrsToGroups, no longer moves the transforms if group has the filter attribute. By @​johnkenny54 in #​1933
• prefixIds, fixed issue where some IDs were not prefixed when style tag contained XML comments. By @​john-neptune in #​1942
• removeEmptyContainers, fixed an issue where we removed empty containers with filters applied via CSS, when it should be skipped. By @​SethFalco in #​2089
• removeHiddenElems, don't remove node if child element has a referenced ID. By @​johnkenny54 in #​1925
• removeHiddenElems, treat path[opacity=0] as a non-rendering node. By @​johnkenny54 in #​1948
• removeUselessDefs, don't remove node if child element has an ID. By @​johnkenny54 in #​1923
• When stringifying path data, include a space before numbers represented in scientific notation. By @​johnkenny54 in #​1961
• No longer crashes when the output (-o argument) ends with a trailing slash to a location that didn't exist. By @​SethFalco in #​1954

Features

• Add VERSION export so get the version of SVGO during runtime. By @​SethFalco in #​2016
• Introduce an isPreset and plugins property to plugins, which are only defined for presets. This will indicate if the plugin is a preset, and return the plugins that are in the preset in the order they are invoked.

SVG Optimization

• convertColors, introduce parameter to convert colors to common casing (lowercase/uppercase). By @​JayLeininger in #​1692
• removeDeprecatedAttrs, new plugin that is disabled by default to remove SVG attributes that are deprecated. By @​jdufresne in #​1869
• removeEditorsNSData, include Boxy SVG namespace in the list of editor namespaces to remove. By @​sisp in #​2008
• removeEditorsNSData, include Krita namespace in the list of editor namespaces to remove. By @​SethFalco in #​2131

Performance

• Use string methods instead of a regular expression when parsing SVGs. By @​SethFalco in #​2133

Developer Experience

• We now generate our type declarations from JSDoc comments instead of maintaining them manually. Types will be much more accurate, include more documentation, and are guaranteed to be in sync with the implementation.

Metrics

Before and after using vectors from various sources, with the default preset of each respective version:

Note: The increase in size from previous versions is from disabling removeViewBox and removeTitle, with the benefit of preserving scalability and accessibility.

Before and after of the browser bundle of each respective version:

v3.3.5

Compare Source

What's Changed

Security

• Backport the removeScriptElement hardening from SVGO v4 in #​2269:
  • reject executable data: URLs and legacy vbscript: URLs
  • sanitize executable HTML inside <foreignObject> elements
  • handle namespace-prefixed SVG anchors and URL schemes containing ASCII tabs or newlines

This addresses GHSA-4vpr-x523-8j87 and GHSA-w27v-7q3p-w38r for the v3 release line.

Support

SVGO v3 is not officially supported; please consider upgrading to SVGO v4. This security fix has been backported, but there is no commitment to backport more complex changes in the future.

See the migration guide from v3 to v4.

v3.3.4

Compare Source

What's Changed

Security

• removeScriptElement, remove JavaScript URIs case-insensitively and make <script> handling namespace aware. By @​SethFalco

Support

SVGO v3 is not officially supported, please consider upgrading to SVGO v4 instead. We've backported this fix as there are security implications, but there is no commitment to do this for more complex changes in future.

Consider reading our Migration Guide from v3 to v4 which should ease the process.