Unbounded Memory Growth in the QUIC PATH_CHALLENGE Handler Unbounded Memory Growth in the QUIC PATH_CHALLENGE Handler (CVE-2026-34183) Severity: Moderate Issue summary: Remote peer may exhaust heap memory of the QUIC server or client by flooding it with packets containing PATH_CHALLENGE frames. Impact summary: A malicious remote peer can cause an unbounded memory allocation which can lead to an abnormal termination of the application acting as a QUIC client or server and a Denial of Service. A remote peer may exhaust heap memory by flooding the local QUIC stack with PATH_CHALLENGE frames. The local QUIC stack allocates a PATH_RESPONSE frame for every PATH_CHALLENGE it receives. The allocated PATH_RESPONSE frame gets freed only when the remote peer acknowledges reception of the PATH_RESPONSE frame which will not be done by a malicious peer. The FIPS modules in 4.0, 3.6, 3.5, 3.4, and 3.0 are not affected by this issue. The QUIC stack is outside of OpenSSL FIPS module boundary. OpenSSL 3.4, 3.5, 3.6 and 4.0 are vulnerable to this issue. OpenSSL 3.0, 1.1.1 and 1.0.2 are not affected by this issue. OpenSSL 4.0 users should upgrade to OpenSSL 4.0.1 OpenSSL 3.6 users should upgrade to OpenSSL 3.6.3 OpenSSL 3.5 users should upgrade to OpenSSL 3.5.7 OpenSSL 3.4 users should upgrade to OpenSSL 3.4.6 The issue was reported by Abhinav Agarwal on 18th March 2026. Fix suggested by Abhinav Agarwal, adapted by Alexandr Nedvedicky.
This issue has been addressed in the following products: Red Hat Enterprise Linux 10 Via RHSA-2026:25237 https://access.redhat.com/errata/RHSA-2026:25237
This issue has been addressed in the following products: Red Hat Enterprise Linux 9 Via RHSA-2026:25239 https://access.redhat.com/errata/RHSA-2026:25239