CVE-2026-111809: Apache Traffic Server allows request smuggling via HEAD requests that carry Content-Length or Transfer-Encoding
CVE-2026-111809 key facts
- CISA KEV
- Not listed (catalogue checked )
- Highest advisory rating
- Medium
- CVSS base score
- 6.9 (Apache), 6.5 (Red Hat)
- Weakness
- CWE-444
- Fixed releases
- Apache: 9.2.16, 10.1.5, 10.2.1
- Red Hat: 9.2.16, 10.1.5, 10.2.1
- Listed by VulniPulse
- Record changed
Ratings, versions and fixes are quoted from the vendor advisories that cover only CVE-2026-111809; each belongs to its advisory, not to every product listed. How records are collected and checked.
How do I fix CVE-2026-111809?
Upgrade to a fixed release named by the vendor:
- Apache: 9.2.16, 10.1.5, 10.2.1
- Red Hat: 9.2.16, 10.1.5, 10.2.1
- Users are recommended to upgrade to version 9.2.16, 10.1.5, or 10.2.1, which fix the issue. (Apache)
Vendor advisories for CVE-2026-111809
Apache
1 advisory- Advisory severityMedium6.9
Medium [CVE-2026-111809] Apache Traffic Server allows request smuggling via HEAD requests that carry Content-Length or Transfer-Encoding
CVE-2026-111809Source published Source updated
Apache Traffic Server allows request smuggling via HEAD requests that carry Content-Length or Transfer-Encoding. 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.
- Affected products in this advisory
- Apache Traffic Server
- Source-reported affected versions
- 8.0.0 through 8.1.11
- 9.0.0 through 9.2.15
- 10.0.0 through 10.1.4
- Source-reported fixed versions
- 9.2.16
- 10.1.5
- 10.2.1
- Mitigation guidance
- Users are recommended to upgrade to version 9.2.16, 10.1.5, or 10.2.1, which fix the issue.
Red Hat
1 advisory- Advisory severityMedium6.5
Medium [CVE-2026-111809] HEAD requests carrying Content-Length or Transfer-Encoding enable request smuggling
CVE-2026-111809Source published Source updated
HEAD requests carrying Content-Length or Transfer-Encoding enable request smuggling. Red Hat rates this moderate (CVSS 6.5). Weakness: CWE-444.
- Related products — impact not confirmed
- No product details extracted. Check the source bulletin.
- Source-reported affected versions
- 8.0.0
- 8.1.11
- 9.0.0
- 9.2.15
3 more entries in the full advisory.
- Source-reported fixed versions
- 9.2.16
- 10.1.5
- 10.2.1
- Mitigation guidance
- No mitigation guidance extracted; consult the source.
References
More Apache advisories
CVE-2026-112381Oct 21, 2026Apache Traffic Server can crash with a null pointer dereferenceCVE-2026-111817Oct 21, 2026Apache Traffic Server can stall a chunked transferCVE-2026-111812Oct 21, 2026Apache Traffic Server's origin_server_auth plugin lets a client force signingCVE-2026-111811Oct 21, 2026Apache Traffic Server's experimental tsmemcache pluginCVE-2026-111810Oct 21, 2026Apache Traffic Server 9.2.15, 10.1.4 and 10.2.0 write one unthrottled diagnostic log lineCVE-2026-111815Oct 21, 2026Apache Traffic Server can resume a TLS session across SNI virtual hosts
Get an email when Apache publishes the next one.
See Apache's last 90 days of advisories first. Then choose one product with live alerts free for life, or a free month of real-time alerts on everything with the severity, the fixed version and the vendor's link (card needed, then US$15/month; we email you before the first charge).
iPhone and Android apps · New on the App Store
Get alerts for new CVEs on your phone.
Choose a whole vendor or a precise platform, then receive matching security advisories by phone notification, email, or both. Coverage follows 34 official vendor sources and 160+ reviewed platform categories.
