Vulnerability Description
Rustls from 0.23.13 before 0.23.45 accepts TLS 1.3 handshake messages at the wrong encryption level when they follow a key-changing message in the same record, because Deframer::aligned does not enforce RFC 8446 record-boundary alignment. A peer or on-path attacker can pack a plaintext EncryptedExtensions with the ServerHello, which rustls accepts unencrypted.
CVSS Score
MEDIUM
Related Weaknesses (CWE)
References
- https://github.com/rustls/rustls/commit/5046bdf8a612b35a2c1a9e168054c1d5c65e7dd7
- https://github.com/rustls/rustls/security/advisories/GHSA-2mjx-qc3c-rqvc
- https://www.vulncheck.com/advisories/rustls-0.23.13-before-0.23.45-tls-1.3-hands
FAQ
What is CVE-2026-123613?
CVE-2026-123613 is a vulnerability with a CVSS score of 5.3 (MEDIUM). Rustls from 0.23.13 before 0.23.45 accepts TLS 1.3 handshake messages at the wrong encryption level when they follow a key-changing message in the same record, because Deframer::aligned does not enfor...
How severe is CVE-2026-123613?
CVE-2026-123613 has been rated MEDIUM with a CVSS base score of 5.3/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-123613?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.