{"id":"GHSA-7j2x-32w6-p43p","summary":"SVG Dimension Capping Bypass via XML Comment Injection in @dicebear/converter ensureSize()","details":"## Summary\n\nThe `ensureSize()` function in `@dicebear/converter` used a regex-based approach to rewrite SVG `width`/`height` attributes, capping them at 2048px to prevent denial of service. This size capping could be bypassed by crafting SVG input that causes the regex to match a non-functional occurrence of `\u003csvg` before the actual SVG root element. When the SVG is subsequently rendered via `@resvg/resvg-js` on the Node.js code path, it renders at the attacker-specified dimensions, potentially causing out-of-memory crashes.\n\n## Details\n\nThe vulnerable function used `String.prototype.replace()` with a non-global regex to find and rewrite the first `\u003csvg` tag's dimensions. Since the regex does not distinguish between `\u003csvg` appearing inside non-element XML constructs and the actual SVG root element, a crafted input can cause the regex to match a decoy instead of the real element, leaving the actual SVG dimensions unclamped.\n\nIn the Node.js rendering path, `renderAsync` from `@resvg/resvg-js` was called without a `fitTo` constraint, so it would render at whatever dimensions the SVG element specified — potentially allocating gigabytes of memory.\n\nThe browser code path is **not** vulnerable because it uses the clamped `size` return value from `ensureSize()` to set `canvas.width` and `canvas.height` directly.\n\n## Impact\n\nAny application that passes untrusted or user-supplied SVG content through `@dicebear/converter`'s Node.js conversion functions (`toPng`, `toJpeg`, `toWebp`, `toAvif`) is vulnerable to denial of service via excessive memory allocation. Note that `@dicebear/converter` can be used independently of DiceBear's avatar generation — any SVG string can be passed to the conversion functions.\n\nThe impact is limited to availability — there is no data disclosure or integrity impact. The browser code path is not affected.\n\n## Fix\n\nThe regex-based approach has been replaced with XML-aware processing using `fast-xml-parser` to correctly identify and modify the SVG root element's attributes. Additionally, a `fitTo` constraint has been added to the `renderAsync` call as defense-in-depth, ensuring the rendered output is always bounded regardless of SVG content.","aliases":["CVE-2026-33418"],"modified":"2026-03-25T21:05:05.061732Z","published":"2026-03-20T20:35:40Z","database_specific":{"github_reviewed_at":"2026-03-20T20:35:40Z","nvd_published_at":"2026-03-24T14:16:30Z","cwe_ids":["CWE-185"],"severity":"HIGH","github_reviewed":true},"references":[{"type":"WEB","url":"https://github.com/dicebear/dicebear/security/advisories/GHSA-7j2x-32w6-p43p"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-33418"},{"type":"PACKAGE","url":"https://github.com/dicebear/dicebear"}],"affected":[{"package":{"name":"@dicebear/converter","ecosystem":"npm","purl":"pkg:npm/%40dicebear/converter"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"9.4.2"}]}],"database_specific":{"last_known_affected_version_range":"\u003c= 9.4.1","source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/03/GHSA-7j2x-32w6-p43p/GHSA-7j2x-32w6-p43p.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"}]}