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Apache Traffic Server skips client certificate checks on resumed TLS

Priority MEDIUM 42CWE-295Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
Spoofing
Confidentiality · integrity · availability
None · None · None
Fix status
No fix listed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-295.

Summary

Apache Traffic Server from 8.0.0 through 8.1.11, from 9.0.0 through 9.2.15, from 10.0.0 through 10.1.4, and 10.2.0 is affected. Improper certificate validation (CWE-295) lets a TLS session resumed on one SNI virtual host skip re-checking the client certificate that the resumed host requires under its verify_client STRICT policy. A remote attacker with no privileges and no user interaction can exploit this over the network. The sources do not report exploitation.

Written with Claude Haiku 5.5 from the sources below · 2026-10-28

Description from the CNA

Apache Traffic Server can resume a TLS session across SNI virtual hosts without re-verifying a client certificate required by the resumed host's verify_client STRICT policy. This issue affects Apache Traffic Server: from 8.0.0 through 8.1.11, from 9.0.0 through 9.2.15, from 10.0.0 through 10.1.4, 10.2.0. Users are recommended to upgrade to version 9.2.16, 10.1.5, or 10.2.1, which fix the issue.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00235 14th percentileScored 2026-11-07
Fix No fix listed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
ApacheApache Traffic Server8.0.0 – 8.1.11; 9.0.0 – 9.2.15; 10.0.0 – 10.1.4; 10.2.0—No fix listedCNA
  • Apache Traffic Server VendorApache Affected 8.0.0 – 8.1.11; 9.0.0 – 9.2.15; 10.0.0 – 10.1.4; 10.2.0 Fixed in — No fix listed CNA

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:a:apache:traffic_server:*:*:*:*:*:*:*:*——Apache
  • cpe:2.3:a:apache:traffic_server:*:*:*:*:*:*:*:* Versions — — ·Apache

Remediation

Upgrade to Apache Traffic Server 9.2.16, 10.1.5, or 10.2.1, which fix the issue. The sources list no fixed version for Apache Traffic Server 8.0.0 through 8.1.11.

Written with Claude Haiku 5.5 from the sources below · 2026-10-28

Fixed in the same release

Records fixed by the same vendor advisory or release, as the CNA lists them.

  • Advisory ·

    Apache Traffic Server — lists.apache.org/thread/r95dq29ywcd1f4x30snxlqmb12z4s4kc

    15 records Highest priority Priority MEDIUM 10 MEDIUM, 5 LOW

    Other records, highest priority first

    • TI-2026-78953 Argument injection in Apache Traffic Server magick pluginPriority MEDIUM 49
    • TI-2026-78957 Malformed 302 responses bypass rejection in Apache Traffic ServerPriority MEDIUM 45
    • TI-2026-78964 Unthrottled logging in Apache Traffic Server allows log-flood DoSPriority MEDIUM 44

Timeline

  1. 2026-10-21 Threatist record created from CVE-2026-111815
  2. 2026-10-21 Alias added: GHSA-h35r-68fc-8f5m
  3. 2026-10-23 CISA SSVC decision points changed
  4. 2026-10-23 Priority changed: MEDIUM → LOW
  5. 2026-10-23 CISA SSVC decision points changed
  6. 2026-10-23 Priority changed: LOW → MEDIUM

References

  • TI-2025-18529 Apache Tomcat: Potential RCE and/or information disclosure and/or information corruption with partial PUT KEVCVSS 3.1CRITICAL 10.0
  • TI-2024-30292 Apache OFBiz: Confused controller-view authorization logic (forced browsing) KEVCVSS 3.1CRITICAL 9.8
  • TI-2024-26062 Apache OFBiz: Unauthenticated endpoint could allow execution of screen rendering code KEVCVSS 3.1CRITICAL 9.8
  • TI-2024-21190 Apache OFBiz: Path traversal leading to RCE KEVCVSS 3.1CRITICAL 9.8
  • TI-2024-18186 Apache HugeGraph-Server: Command execution in gremlin KEVCVSS 3.1CRITICAL 9.8
  • TI-2023-25106 Deserialization of untrusted data in Apache ActiveMQ KEVCVSS 3.1CRITICAL 10.0
See all 4053 →

Sources