Integer overflow in Cesanta Mongoose
CVE-2025-51495
An integer overflow vulnerability exists in the WebSocket component of Mongoose 7.5 thru 7.17. By sending a specially crafted WebSocket request, an attacker can cause the application to crash. If downstream vendors integrate this component improperly, the issue may lead to a buffer overflow.
Vulnerability class: Integer Overflow
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.004 (34.5th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 34th percentile — 34.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.004 · change: 0.000
Affected products
Weakness classification (CWE)
Public proof-of-concept exploits
References
- github.com/cesanta/mongoose (Product)
- github.com/cesanta/mongoose/pull/3131 (Patch, Issue Tracking)
- github.com/cainiao159357/CVE-2025-51495 (Exploit)
Frequently asked questions
- What is CVE-2025-51495?
- CVE-2025-51495 is a high-severity vulnerability in Cesanta Mongoose, classified under Integer Overflow or Wraparound. CVSS score: 7.5/10. Published 2025-09-29.
- How severe is CVE-2025-51495?
- High severity. CVSS v3 base score is 7.5 out of 10.
- Is CVE-2025-51495 known to be exploited?
- 3 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.