CVE-2026-112958 ApostropheCMS: Stored XSS via Unescaped Widget Style Attribute Serialization
- Exploited in the wild
- Not known
- Fix
- Available
What is CVE-2026-112958?
CVE-2026-112958 is a medium-severity vulnerability in apostrophecms apostrophe, published on 20 Oct 2026.
Official description
ApostropheCMS is an open-source Node.js content management system. Prior to 4.34.0, a project-defined free-form widget style field can carry an editor-controlled quote into an inline style attribute because the wrapper serializer does not apply HTML-attribute encoding. The quote can terminate the style attribute and inject executable attributes when published content, or an affected draft viewed by a higher-privileged user, is rendered. This issue is fixed in version 4.34.0.
Weakness: CWE-79
Which versions are affected by CVE-2026-112958?
2 open source packages ship an affected version, including apostrophe.
| Package | Affected | Fixed in |
|---|---|---|
apostrophe npm | All versions | 4.34.0 |
apostrophe npm | All versions | 4.34.0 |
How do I fix CVE-2026-112958?
Upgrade apostrophe to 4.34.0 or later.
Is CVE-2026-112958 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-112958 exists.
Sources
Also known as GHSA-7jg5-frgc-c67w.