CVE-2026-113659 ApostropheCMS: Client-side Prototype Pollution in apos.http.parseQuery leading to DOM-based XSS against authenticated users
- Exploited in the wild
- Not known
- Fix
- Available
What is CVE-2026-113659?
CVE-2026-113659 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 4.33.0, an unauthenticated attacker can send a crafted link whose query string is automatically parsed by apos.http.parseQuery when an authenticated victim loads a page with the admin bundle. The parser accepts the special __proto__, constructor, and prototype path keys, allowing browser prototype mutation that can reach an unsafe DOM sink and execute script in the victim's session; anonymous visitors do not load the affected admin context. This issue is fixed in version 4.33.0.
Which versions are affected by CVE-2026-113659?
2 open source packages ship an affected version, including apostrophe.
| Package | Affected | Fixed in |
|---|---|---|
apostrophe npm | All versions | 4.33.0 |
apostrophe npm | All versions | 4.33.0 |
How do I fix CVE-2026-113659?
Upgrade apostrophe to 4.33.0 or later.
Is CVE-2026-113659 being exploited?
There is no known exploitation of CVE-2026-113659 in the wild and no public exploit code.
Sources
Also known as GHSA-m2m5-rw3w-cwmj.