Apache Traffic Server skips client certificate checks on resumed TLS
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
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
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
- 2026-10-21 Threatist record created from CVE-2026-111815
- 2026-10-21 Alias added: GHSA-h35r-68fc-8f5m
- 2026-10-23 CISA SSVC decision points changed
- 2026-10-23 Priority changed: MEDIUM → LOW
- 2026-10-23 CISA SSVC decision points changed
- 2026-10-23 Priority changed: LOW → MEDIUM
References
More Apache vulnerabilities
- 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
Sources
- CVE-2026-111815 · CVE Program
- CVE-2026-111815 · NVD
- FIRST EPSS
- GHSA-h35r-68fc-8f5m · GitHub Advisory Database · CC BY 4.0
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