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.

Attack Vector Network

Attack Complexity Low

Privileges Required None

Attack Requirements None

User Interaction None

Vulnerable System Confidentiality Impact Low

Vulnerable System Integrity Impact None

Vulnerable System Availability Impact None

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact Low

Integrity Impact None

Availability Impact None

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Key SSVC decision points have not yet been added.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
rustls rustls unaffected
Version Status Constraints
0.23.13 affected < 0.23.45
0.23.45 unaffected —

No data.

No data.

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Project Subscriptions

Vendors Products
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Advisories

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Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://github.com/rustls/rustls/commit/5046bdf8a612b35a2c1a9e168054c1d5c65e7dd7 cve-icon cve-icon
https://github.com/rustls/rustls/security/advisories/GHSA-2mjx-qc3c-rqvc cve-icon cve-icon
https://www.vulncheck.com/advisories/rustls-0.23.13-before-0.23.45-tls-1.3-handshake-encryption-level-bypass cve-icon cve-icon
History

Sun, 08 Nov 2026 01:45:00 +0000

Type Values Removed Values Added
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.
Title Rustls 0.23.13 before 0.23.45 TLS 1.3 Handshake Encryption Level Bypass
First Time appeared Rustls Project
Rustls Project rustls
Weaknesses CWE-20
CPEs cpe:2.3:a:rustls_project:rustls:*:*:*:*:*:*:*:*
Vendors & Products Rustls Project
Rustls Project rustls
References
Metrics cvssV3_1

{'score': 5.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N'}

cvssV4_0

{'score': 6.9, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-11-08T01:38:37.574Z

Reserved: 2026-11-06T01:02:39.794Z

Link: CVE-2026-123613

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-11-08T02:16:56.780

Modified: 2026-11-08T02:16:56.780

Link: CVE-2026-123613

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-11-08T03:15:08Z

Weaknesses