DiceBear: SVG injection via the unescaped rotate option in @dicebear/core (and fontSize/fontWeight in @dicebear/initials)

Summary

@dicebear/core builds avatar SVGs from caller-supplied options. The numeric rotate option is interpolated into an SVG transform attribute without XML-escaping. It is typed as a number, but nothing checks the type at runtime, so a string value passes straight through and can break out of the attribute to inject arbitrary SVG markup.

This is the same root cause as CVE-2026-33311 (GHSA-mr9r-mww3-v6gv), which escaped the string options backgroundColor, fontFamily, and textColor but did not cover rotate. @dicebear/initials has the same gap in its numeric fontSize and fontWeight options.

Impact

Cross-site scripting (CWE-79). When the generated avatar is rendered inline (for example via innerHTML) or served as image/svg+xml and opened directly, injected markup such as an <image onerror> handler runs script in the page's origin.

Exploitation requires the application to pass untrusted input into one of these options:

• rotate (@dicebear/core)
• fontSize, fontWeight (@dicebear/initials)

In most integrations these options are set by the developer and only seed is user-controlled, so the vulnerable configuration is uncommon. Applications that use trusted, hardcoded values for these options are not at risk.

Patches

Fixed in @dicebear/core 9.4.3 and @dicebear/initials 9.4.3: the values are now XML-escaped before being written into the SVG, matching the CVE-2026-33311 fix. Upgrade to 9.4.3 or later.

The 5.x through 8.x lines share the same flaw but are end-of-life and will not receive a backport; upgrade to 9.4.3. The 10.x line is not affected.

Workarounds

If you cannot upgrade, coerce the affected options to a number before passing them to createAvatar:

rotate: Number(userInput) || 0,

Credits

Reported by @rz1027.