CVSS 4.0
6.9 mediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:NCVE-2026-123613
Medium (6.9) in rustls rustls. EPSS 0.2% estimated probability of exploitation activity in the next 30 days. Fixed in rustls 0.23.45.
On this page
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.
Severity
CVSS 3.1
5.3 mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N- EPSS
- 0.2% estimated probability of exploitation activity in the next 30 days; 5th percentile. Scored 2026-11-10. A forecast for this CVE across the internet, not for your own systems.
- CWE
- CWE-20 Improper Input Validation
- OWASP Top 10
- A05:2025 Injection
- Published
- NVD analysis
- Awaiting analysis
- Record from
- the NVD, synced
Ask an AI about this CVE
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Explain CVE-2026-123613 for an engineer deciding whether to act. Use https://cve.bz/api/public/cves/CVE-2026-123613?via=ask-ai-copy and https://cve.bz/cve/CVE-2026-123613?via=ask-ai-copy as the source of truth: what is affected and which versions fix it, whether it is in CISA KEV, public exploits, and its EPSS (an internet-wide 30-day estimate of exploitation activity, not a forecast for my systems). If they give no fixed versions, use the CVE record https://cveawg.mitre.org/api/cve/CVE-2026-123613 or the vendor advisory, not third-party mirrors. Tell me how to check whether I am affected and how to verify a fix. Cite the sources and say where they are uncertain.Opens a third-party assistant; its answer is its own, not cve.bz's. The prompt holds only this CVE's id and public links.
Affected
Versions
From the CNA's record in the CVE List.
| Product | Affected |
|---|---|
| rustls | from 0.23.13 before 0.23.45 |
Packages (OSV)
| Advisory | Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|---|
| GHSA-2mjx-qc3c-rqvc | crates.io | rustls | >=0.23.13 <0.23.45 | 0.23.45 |
| RUSTSEC-2026-0285 | crates.io | rustls | >=0.23.13 <0.23.45 | 0.23.45 |
Linux distributions
| Distribution | Release | Package | Fixed in | Advisory |
|---|---|---|---|---|
| Debian | 12, 13 | rust-rustls | no fix listed | DEBIAN-CVE-2026-123613 |
| Debian | 14 | rust-rustls | 0.23.45+ds-1 | DEBIAN-CVE-2026-123613 |
| Ubuntu | 24.04:LTS, 26.04:LTS, 26.10 | rust-rustls | no fix listed | UBUNTU-CVE-2026-123613 |
From the distributions' data via OSV.dev: the Debian Security Tracker; Ubuntu Security Notices © Canonical Ltd., CC BY-SA 4.0. Modified: reformatted and linked to CVE records. Credits. On the distributions' own pages: Debian · Ubuntu.
Attack patterns (CAPEC)
The attack patterns MITRE's CAPEC relates to this record's weaknesses, as MITRE names them. Credits. More on the page of CWE-20 (51).