Medium severity · published Oct 20, 2026
CVE-2026-112958
ApostropheCMS: Stored XSS via Unescaped Widget Style Attribute Serialization
5.4
CVSS
0.3%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
Required
Confidentiality
Low
Integrity
Low
Availability
None
Scope
Changed
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 23% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
AP
apostrophe · apostrophecms
< 4.34.0 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-112958
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-112958
github.com
https://github.com/apostrophecms/apostrophe/commit/06e4b377f3c360f9e89c32dccd7e505ad5ddf498
github.com
https://github.com/apostrophecms/apostrophe/commit/40b989b1a9dd23d30029b8ce7668634265cfe5ea
github.com
https://github.com/apostrophecms/apostrophe/releases/tag/apostrophe@4.34.0
github.com
https://github.com/apostrophecms/apostrophe/security/advisories/GHSA-7jg5-frgc-c67w
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