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CVE-2026-123612VulnerabilityPublished

rustls 0.23.44 and 0.23.45 contain an information disclosure vulnerability that sends application data buffered before

Source GCVE Database

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Authoritative record:CVE-2026-123612· Medium 4.6

Not known to be exploited · CVSS 4.6 Medium : upgrade to 0.23.46 when convenient.

Data as of 8 Nov 2026, 06:21 UTC

CVSS 4.0 base score
4.6Medium
How severe the flaw is on the 0–10 CVSS scale.

Thin evidence

One scorer or none
CVSS scores by source
CNA (VulnCheck)CVSS 4.04.6
CNA (VulnCheck)CVSS 3.12.3
Patch
Available – fixed in 0.23.46
CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 8 Nov 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 7 Nov 2026.

What to do

Upgrade rustls to 0.23.46.

Affected software

ProductAffectedFixed in
rustlsrustlsAffected
  • >=0.23.44 <0.23.46
Fixed in
  • 0.23.46
crates.iorustlspkg:cargo/rustlsOther threatsAffected
  • >=0.23.44 <0.23.46
Fixed in
  • 0.23.46

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

If you cannot patch yet, users should consider avoiding versions 0.23.44 and 0.23.45 or disabling Encrypted Client Hello if feasible.

Description

Rustls versions 0.23.44 and 0.23.45 have an information disclosure vulnerability where application data buffered before handshake completion can be sent to the client-facing server if Encrypted Client Hello (ECH) is rejected. This occurs because plaintext data is queued and sent prematurely, exposing data intended for an inner server to the authenticated public_name server.

References

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