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No exploitation reportedFix availableAwaiting NVD analysis

CVE-2026-123613

Rustls 0.23.13 before 0.23.45 TLS 1.3 Handshake Encryption Level Bypass

No exploitation reported by the sources we read.

  • Published2026-11-08
  • Fixed in0.23.45
  • WeaknessCWE-20

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

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.

Timeline

dates in UTC
  1. 2026-11-0801:38CVE publishedCNA

Versions per branch

OSV
rustls
BranchAffectedFixed in
0.23≥ 0.23.13, < 0.23.450.23.45

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Products declared by the CNA1 product

As VulnCheck, the CNA that assigned this CVE, declared them in the CVE record; versions as written.

  • rustlsother versions: not affected
    Affected
    • ≥ 0.23.13, < 0.23.45fixed in 0.23.45semver

    Not affected = 0.23.45

Source: the CNA record (CVE Program), © The MITRE Corporation,CVE Terms of UseCVE recordupdated 2026-11-08

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • rust-rustlsDebian:14all versions · fixed in 0.23.45+ds-1
  • rust-rustlsDebian:13all versions · no fixed version listed
  • rust-rustlsDebian:12all versions · no fixed version listed

Full record on NVD

Fix

  1. Update rustls to 0.23.45

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Metasploit modules
none listed
Metasploit Framework

Sources

  • CNACVSS 4.06.92026-11-08
  • CNACVSS 3.15.32026-11-08
  • NVDCVSS 3.15.3read 2026-11-08
  • CNAweakness (CWE)CWE-202026-11-08
  • NVDweakness (CWE)CWE-20read 2026-11-08
  • FIRST EPSSEPSS score0.2 %2026-11-08
  • OSVaffected packages—
  • GitHub AdvisoriesadvisoryMODERATE2026-10-05

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
CVSS 4.0 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Published
2026-11-08
Last Modified
2026-11-08
NVD status
Received
GitHub Advisory
GHSA-2mjx-qc3c-rqvc GHSA-rp7q-jxfg-4g6g

Frequently asked questions

What is CVE-2026-123613?

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.

Is CVE-2026-123613 actively exploited?

Active exploitation of CVE-2026-123613 has not been confirmed. Its EPSS score was 0.2% on 2026-11-08, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-123613?

CVE-2026-123613 has a CVSS v3 base score of 5.3 (MEDIUM severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N.

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