Rustls 0.23.13 before 0.23.45 TLS 1.3 Handshake Encryption Level Bypass
- Exploited
- No known exploitation
- Fix
- Fixed in 0.23.45
- Who is exposed
- Not reported
Do first: Upgrade to a fixed version: 0.23.45.
- Published
- Last modified
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 24/100 · provisional
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
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.
cve.now Index
- Exploitation?/40Unknown. No CISA SSVC exploitation rating yet
- Exposure17/25No login or user action needed per the CVSS vector, reachable over the network without a login · Unknown: No advisory context yet
- Reach?/20Unknown. No tracked technology or package matched
- Severity6.9/10CVSS 6.9
- No patch0/5No signal
What would change the score
- Would score about 69 if added to CISA KEV
- Would score about 64 if CISA's SSVC rates exploitation active
- Would score about 29 if advisories confirm default setups are exposed
What to do
Upgrade to a fixed version: 0.23.45.
Timeline
- CVE published
- First seen by cve.now
Affected versions
- rustls rustls
From 0.23.13 · fixed in 0.23.45
Evidence 3
- Advisory
- Patch
- Link
Corrections
None so far.
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Questions about CVE-2026-123613
Is CVE-2026-123613 being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data
Which versions are affected by CVE-2026-123613?
rustls: from 0.23.13 before 0.23.45.Source: cve.now feed data
How do I fix CVE-2026-123613?
Upgrade to a fixed version: 0.23.45.Source: cve.now feed data