CVE-2025-11679: warmcat libwebsockets · Out-of-bounds Read
Affects warmcat libwebsocketsSource CVE Database V5
Not known to be exploited · CVSS 5.9 Medium.
Data as of 25 Oct 2026, 19:02 UTC
- EPSS
- 0.3% chance of exploitation in 30 days – higher than 33% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 20 Oct 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-25.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| warmcat libwebsockets | Affected
| Fixed in– |
AI-suggested
1. Disable the LWS_WITH_UPNG flag during compilation if PNG processing via libwebsockets is not required, thereby eliminating the vulnerable code path. 2. Monitor the official warmcat libwebsockets repository and security advisories for patches addressing CVE-2025-11679 and apply them promptly once available. 3. Implement web content filtering and URL reputation services to block access to untrusted or suspicious websites that could host malicious PNG files. 4. Employ runtime application monitoring to detect abnormal crashes or memory errors in applications using libwebsockets, enabling rapid incident response. 5. For embedded or IoT devices, coordinate firmware updates that include patched libwebsockets versions and ensure secure update mechanisms. 6. Conduct security reviews of web-facing applications using libwebsockets to identify and isolate vulnerable components. 7. Educate users about the risks of visiting untrusted websites and the importance of cautious web browsing to reduce user interaction risk.
Description
Out-of-bounds Read in lws_upng_emit_next_line in warmcat libwebsockets allows, when the LWS_WITH_UPNG flag is enabled during compilation and the HTML display stack is used, to read past a heap allocated buffer possibly causing a crash, when the user visits an attacker controlled website that contains a crafted PNG file with a big height dimension.