CVE-2026-42764

Description

Issue summary: Receiving a QUIC initial packet with an invalid token may trigger a NULL pointer dereference in the OpenSSL QUIC server with address validation disabled. Impact summary: NULL pointer dereference typically causes abnormal termination of the affected QUIC server process and a Denial of Service. If the address validation is disabled in the OpenSSL QUIC server implementation, an attacker can crash the server by sending an initial packet with an invalid or expired token. By default, the client address validation is enabled in the OpenSSL QUIC server implementation, which makes the default configuration not vulnerable to this issue. However if the SSL_LISTENER_FLAG_NO_VALIDATE is used with the SSL_new_listener() call, the address validation is disabled making the vulnerable code reachable. The FIPS modules in 4.0, 3.6, 3.5, 3.4, and 3.0 are not affected by this issue, as the affected code is outside the OpenSSL FIPS module boundary.

PUBLISHED Reserved 2026-04-29 | Published 2026-06-09 | Updated 2026-06-10 | Assigner openssl

Problem types

CWE-476 NULL Pointer Dereference

Product status

Credits

Sunwoo Lee (KENTECH) reporter

Hyuk Lim (KENTECH) reporter

Seunghyun Yoon (KENTECH) reporter

Sunwoo Lee (KENTECH) remediation developer

Hyuk Lim (KENTECH) remediation developer

Seunghyun Yoon (KENTECH) remediation developer

References

openssl-library.org/news/secadv/20260609.txt (OpenSSL Advisory) vendor-advisory

github.com/...ommit/bf29a458c1a231eca87e384c62b9c2553fa57a91 (4.0.1 git commit) patch

github.com/...ommit/a45a0aba8095682c88ff4fc4a784892b8c6f0677 (3.6.3 git commit) patch

github.com/...ommit/5e3ed291b8af0b03d5d3b9e56a1da69a187e9729 (3.5.7 git commit) patch

cve.org (CVE-2026-42764)

nvd.nist.gov (CVE-2026-42764)

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