CVE-2026-123613
Rustls 0.23.13 before 0.23.45 TLS 1.3 Handshake Encryption Level Bypass
CVSS Score
5.3
EPSS Score
0.0%
EPSS Percentile
0th
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.
| CWE | CWE-20 |
| Vendor | rustls |
| Product | rustls |
| Published | Nov 8, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
None
Availability
None
Affected Versions
rustls / rustls
0.23.13 < 0.23.45
References
github.com: https://github.com/rustls/rustls/security/advisories/GHSA-2mjx-qc3c-rqvc github.com: https://github.com/rustls/rustls/commit/5046bdf8a612b35a2c1a9e168054c1d5c65e7dd7 vulncheck.com: https://www.vulncheck.com/advisories/rustls-0.23.13-before-0.23.45-tls-1.3-handshake-encryption-level-bypass
Credits
🔍 randombit