What’s Vulnerable › Vulnerabilities
CVE-2026-65100: Apache Traffic Server: HPACK encoder desynchronizes from the decoder after a failed header encode
- Severity: medium (CVSS 4.8 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.6% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2026-07-29 · updated 2026-10-01
- Weakness: CWE-696
Description
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 8.1.11, 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 products
- Apache Software Foundation Apache Traffic Server: from 8.0.0 through 8.1.9; from 9.0.0 before 9.2.15; from 10.0.0 before 10.1.4 — fixed in 10.1.4, 9.2.15
How to fix
Upgrade to a fixed version: Apache Software Foundation Apache Traffic Server 10.1.4, 9.2.15. Check the vendor advisory for mitigations.
References
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