Client crash via PNG width integer overflow
Published Oct 20, 2025 · Updated Oct 20, 2025
Out-of-bounds write in affected libwebsockets releases allows remote attackers to crash clients through a crafted PNG file. A large PNG width overflows the heap-allocation size, so unfilter_scanline writes decoded bytes past the undersized buffer. Exploitation requires an LWS_WITH_UPNG build, the HTML display stack, and active user interaction with an attacker-controlled website; the published impact is a client crash.
Summary
What happened
Out-of-bounds write in affected libwebsockets releases allows remote attackers to crash clients through a crafted PNG file. A large PNG width overflows the heap-allocation size, so unfilter_scanline writes decoded bytes past the undersized buffer. Exploitation requires an LWS_WITH_UPNG build, the HTML display stack, and active user interaction with an attacker-controlled website; the published impact is a client crash.
The record
- CVE
- CVE-2025-11680
- Published
- Oct 20, 2025
- Updated
- Oct 20, 2025
- Vendor
- libwebsockets
- Product
- libwebsockets
- Classifications
- CWE-787, CAPEC-100, T1203
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Oct 20, 2025CVE publishedPublication date reported by the CVE source.
- Oct 20, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=4.0 <=4.3.6
- Affected versionversion=4.0 <=4.4.2
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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