Expected behavior violation in OpenSSL - CVE-2026-35191
Published: September 30, 2026
Vulnerability identifier: #VU152954
CSH Severity: Low
CVSS v4: 6.3 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-35191
CWE-ID: CWE-440
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to amplify a distributed denial-of-service attack.
The vulnerability exists due to an expected behavior violation in the QUIC server unvalidated credit computation when processing a datagram containing multiple QUIC packets. A remote attacker can send a multi-packet QUIC datagram to amplify a distributed denial-of-service attack.
The server must be configured without client address validation.
Affected software
OpenSSL
Debian Linux
openssl (Debian package)
Debian Linux
openssl (Debian package)
How to mitigate CVE-2026-35191
Install security update from vendor's website.
OpenSSL - addressed in versions 1.0.2zs, 1.1.1zj, 3.0.23, 3.4.8, 3.5.9, 3.6.5, 4.0.3
openssl (Debian package) - update to 3.5.7-1~deb13u3
openssl (Debian package) - update to 3.5.7-1~deb13u3