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TI-2026-86751 Aliases CVE-2026-123609GHSA-67mj-442h-2gp6

Secret key material exposed through Debug formatting in Rustls

Priority LOW 34CWE-212Published · Updated

Key facts

Attack vector
Local
Privileges required
High
User interaction
Passive
Attack complexity
High
Attack requirements
Present
Impact type
—
Confidentiality · integrity · availability
High · None · None
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA.

Summary

Rustls before 0.23.46 and from 0.24.0-dev.1 before 0.24.0-dev.2 contains an information disclosure flaw where derived Debug formatting of client session values exposes secret key material (CWE-212). Custom ClientSessionStore implementations that log Tls12ClientSessionValue or Tls13ClientSessionValue write TLS 1.2 master secrets or TLS 1.3 resumption PSKs into those logs. A local attacker with high privileges who can read the logs can obtain these secrets.

Written with Claude Haiku 5.5 from the sources below · 2026-11-08

Description from the CNA

Rustls before 0.23.46 and 0.24.0-dev.1 before 0.24.0-dev.2 contains an information disclosure vulnerability where derived Debug formatting of client session values exposes secret key material. Custom ClientSessionStore implementations that log Tls12ClientSessionValue or Tls13ClientSessionValue can leak TLS 1.2 master secrets or TLS 1.3 resumption PSKs to log readers.

Why it matters now

Fix Fixed rustls (rustls): 0.23.46, 0.24.0-dev.2

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

VendorProductAffected versionsFixed inStatusSource
rustlsrustlsbefore 0.23.46; 0.24.0-dev.1 to before 0.24.0-dev.20.23.46, 0.24.0-dev.2Patch availableCNA
  • rustls Vendorrustls Affected before 0.23.46; 0.24.0-dev.1 to before 0.24.0-dev.2 Fixed in 0.23.46, 0.24.0-dev.2 Patch available CNA

Remediation

Update rustls to 0.23.46 or 0.24.0-dev.2, the fixed versions.

Written with Claude Haiku 5.5 from the sources below · 2026-11-08

  • Fix · CNA rustls (rustls) Fixed in 0.23.46, 0.24.0-dev.2

Timeline

  1. 2026-11-08 Threatist record created from CVE-2026-123609
  2. 2026-11-08 Alias added: GHSA-67mj-442h-2gp6

References

Advisory 1

  • TI-2026-63063 rustls-webpki before 0.103.13 Panic via empty BIT STRING CVSS 4.0HIGH 8.7
  • TI-2026-86755 Rustls accepts handshake messages at the wrong encryption level CVSS 4.0MEDIUM 6.9
  • TI-2026-86753 Key exchange downgrade in rustls via unauthenticated ServerHello CVSS 4.0MEDIUM 6.3
  • TI-2026-86752 Uncontrolled memory allocation in rustls Brotli certificate decompression CVSS 4.0MEDIUM 6.3
  • TI-2024-21532 Rustls vulnerable to an infinite loop in rustls::conn::ConnectionCommon::complete_io() with proper client input CVSS 3.1HIGH 7.5
  • TI-2026-86754 Application data sent to public_name server when rustls rejects ECH CVSS 4.0MEDIUM 4.6
See all 9 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences