CVE-2026-71553 ApostropheCMS: 2nd-order prototype pollution via PATCH leading to single-request persistent DoS
An authenticated editor can cause a persistent denial of service in ApostropheCMS by exploiting prototype pollution via a PATCH request.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-71553?
CVE-2026-71553 is a high-severity vulnerability in apostrophecms apostrophe, published on 17 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
ApostropheCMS is an open-source Node.js content management system. In 4.32.0 and earlier, PATCH /api/v1/article/:id accepts the inherited path toString.call and passes it through the utility module to apos.util.set() and apos.util.get(), allowing an authenticated editor to overwrite the shared Object.prototype.toString function's call property and cause a persistent process-wide denial of service until restart.
Weakness: CWE-1321
Which versions are affected by CVE-2026-71553?
2 open source packages ship an affected version, including apostrophe.
| Package | Affected | Fixed in |
|---|---|---|
apostrophe npm | All versions | 4.32.1 |
apostrophe npm | All versions | 4.32.1 |
How do I fix CVE-2026-71553?
Upgrade apostrophe to 4.32.1 or later.
Is CVE-2026-71553 being exploited?
There is no known exploitation of CVE-2026-71553 in the wild and no public exploit code.
Sources
Also known as GHSA-vmg4-6gfg-83qx.