CVE-2026-65100: Apache Traffic Server: HPACK encoder desynchronizes from the decoder after a failed header encode
Apache Traffic Server updates the HTTP/2 HPACK dynamic table before confirming the header block encoded successfully, so an encode failure leaves the encoder out of sync with the peer decoder and corrupts subsequent header blocks on the connection.
This issue affects Apache Traffic Server: from 8.0.0 through 8.1.9, from 9.0.0 through 9.2.14, from 10.0.0 through 10.1.3.
Users are recommended to upgrade to version 9.2.15 or 10.1.4, which fix the issue.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
Apache Traffic Serverto a version that resolves this vulnerability.Fixed in 9.2.15 - Upgrade
Upgrade
Apache Traffic Serverto a version that resolves this vulnerability.Fixed in 10.1.4
Event History
Frequently Asked Questions
What is the severity of CVE-2026-65100?
The severity of CVE-2026-65100 is classified as medium with a score of 4.8.
How do I fix CVE-2026-65100?
To fix CVE-2026-65100, update your Apache Traffic Server to the latest version where the issue has been addressed.
What systems are affected by CVE-2026-65100?
CVE-2026-65100 affects Apache Traffic Server versions starting from 8.0.
What is the impact of CVE-2026-65100?
CVE-2026-65100 can cause header blocks on a connection to become corrupted due to the encoder being out of sync with the decoder.
Is user interaction required to exploit CVE-2026-65100?
No, CVE-2026-65100 does not require user interaction to be exploited.