Out-of-bounds Write Affecting libwebsockets package, versions <4.3.5-1+deb13u3
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-ECHOLATEST-LIBWEBSOCKETS-20044348
- published22 Sept 2026
- disclosed15 Sept 2026
Introduced: 15 Sep 2026
CVE-2026-19773 (opens in a new tab)How to fix?
Upgrade Echo:latest libwebsockets to version 4.3.5-1+deb13u3 or higher.
NVD Description
Note: Versions mentioned in the description apply only to the upstream libwebsockets package and not the libwebsockets package as distributed by Echo.
See How to fix? for Echo:latest relevant fixed versions and status.
libwebsockets HTTP/2 HPACK Path Header Parsing Out-Of-Bounds Write Remote Code Execution Vulnerability. This vulnerability allows remote attackers to execute arbitrary code on affected installations of libwebsockets. Authentication is not required to exploit this vulnerability.
The specific flaw exists within the parsing of HTTP/2 HPACK path header. The issue results from the lack of proper validation of user-supplied data, which can result in a write past the end of an allocated buffer. An attacker can leverage this vulnerability to execute code in the context of the current process. Was ZDI-CAN-31036.