CVE-2026-71553: ApostropheCMS: 2nd-order prototype pollution via PATCH leading to single-request persistent DoS
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.
Other sources
The vulnerability is a single-request persistent DoS by submitting e.g. "PATCH /api/v1/article/<id>" with a valid editor session and body of {"toString.call":"x"}, overwriting the global toString function with value x.
Fabian
— GitHub
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
ApostropheCMSto a version that resolves this vulnerability.Fixed in 4.32.0 - Operational
After applying the fix, restart the ApostropheCMS process to clear the persistent, process-wide denial of service caused by overwriting Object.prototype.toString.call.
Event History
Frequently Asked Questions
What is the severity of CVE-2026-71553?
CVE-2026-71553 has a risk rating of 48, indicating a moderate severity level.
How do I fix CVE-2026-71553?
To fix CVE-2026-71553, you should upgrade ApostropheCMS to version 4.32.1 or later.
What type of vulnerability is CVE-2026-71553?
CVE-2026-71553 is a second-order prototype pollution vulnerability leading to potential denial of service.
Who is affected by CVE-2026-71553?
CVE-2026-71553 affects all users running ApostropheCMS versions 4.32.0 and earlier.
What component of ApostropheCMS does CVE-2026-71553 affect?
CVE-2026-71553 specifically affects the PATCH /api/v1/article/:id endpoint in ApostropheCMS.