ZDI-26-590: libwebsockets HTTP/2 HPACK Path Header Parsing Out-Of-Bounds Write Remote Code Execution Vulnerability
ZDI disclosed CVE-2026-19773, an unauthenticated out-of-bounds write allowing remote code execution in libwebsockets HTTP/2 HPACK parsing, rated CVSS 9.8.
The Zero Day Initiative published advisory ZDI-26-590 for an out-of-bounds write vulnerability in libwebsockets' HTTP/2 HPACK path header parsing. A remote attacker can execute arbitrary code on affected installations without authentication. The flaw is tracked as CVE-2026-19773 and carries a CVSS score of 9.8.
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