CVE-2026-111815 Apache Software Foundation CVE debrief

Who should care

Defenders responsible for Apache Traffic Server deployments should assess exposure and prioritize upgrading to fixed versions. This includes reviewing the affected versions, assessing the potential impact, and planning for upgrades or mitigations. Defenders should also monitor for potential TLS session ticket resumption bypasses and review compensating controls for exposed systems.

Why it matters

Defenders should prioritize upgrading to fixed versions to prevent potential TLS session ticket resumption bypasses. This issue affects Apache Traffic Server versions 8.0.0 through 8.1.11, 9.0.0 through 9.2.15, 10.0.0 through 10.1.4, and 10.2.0.

• Verify client certificate enforcement for TLS sessions
• Assess exposure of affected versions
• Prioritize upgrading to fixed versions
• Monitor for potential TLS session ticket resumption bypasses

Technical summary

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 allows an attacker to bypass the verify_client STRICT enforcement, potentially leading to security issues. The issue affects Apache Traffic Server versions 8.0.0 through 8.1.11, 9.0.0 through 9.2.15, 10.0.0 through 10.1.4, and 10.2.0. Users are recommended to upgrade to version 9.2.16, 10.1.5, or 10.2.1 to fix the issue. The vulnerability is caused by the TLS session ticket resumption feature, which can be exploited to bypass security controls.

Defensive priority

Defenders should prioritize upgrading to fixed versions to prevent potential TLS session ticket resumption bypasses.

Recommended defensive actions

• Upgrade to version 9.2.16, 10.1.5, or 10.2.1
• Review and update affected versions
• Monitor for potential TLS session ticket resumption bypasses
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up
• Review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance
• Plan vendor-supported updates or mitigations through normal change control where exposure is confirmed
• Check relevant monitoring, detection, and logs for exposed assets that need extra review

Evidence notes

The CVE record and source item provide details on the vulnerability and affected versions. The issue is caused by the TLS session ticket resumption feature in Apache Traffic Server, which can bypass per-SNI verify_client STRICT enforcement. Evidence is limited to the information provided in the CVE record and source item. Defenders should verify the affected versions and assess exposure. The CVE record was published on 2026-10-21T19:13:55.811Z and has not been modified since then.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.