CVE-2026-33418 — @dicebear/converter
HIGHCVE-2026-33418 is a high-severity (CVSS 7.5) CWE-185 vulnerability in @dicebear/converter. A fix is available for @dicebear/converter — see the affected versions and patch details below.
@dicebear/converter ensureSize() Vulnerable to SVG Dimension Capping Bypass via XML Comment Injection
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-33418.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2026-33418 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 378,567 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
@dicebear/converternpmDescription
Summary
The 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 <svg 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.
Details
The vulnerable function used String.prototype.replace() with a non-global regex to find and rewrite the first <svg tag's dimensions. Since the regex does not distinguish between <svg 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.
In 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.
The browser code path is not vulnerable because it uses the clamped size return value from ensureSize() to set canvas.width and canvas.height directly.
Impact
Any 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.
The impact is limited to availability — there is no data disclosure or integrity impact. The browser code path is not affected.
Fix
The 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.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | @dicebear/converter | all versions | 9.4.2npm install @dicebear/converter@9.4.2 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @dicebear/converter, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update @dicebear/converter to 9.4.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-33418 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-33418 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2026-33418. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-33418 in your dependencies?
O3 Security finds CVE-2026-33418 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.