HTTP/2 Header Encoding Vulnerability in Apache Traffic Server
CVE-2026-65100

6.3MEDIUM

Key Information:

Vendor

Apache
Status
Apache Traffic Server
Vendor
CVE Published:
29 July 2026

What is CVE-2026-65100?

A vulnerability in Apache Traffic Server relates to improper updating of the HTTP/2 HPACK dynamic table prior to the confirmation of successful header block encoding. This oversight can lead to an encoder and decoder desynchronization in cases of encoding failures, subsequently corrupting subsequent header blocks within the active connection. Affected users are advised to upgrade to versions 9.2.15 or 10.1.4 to mitigate this issue.

Affected Version(s)

Apache Traffic Server 8.0.0 <= 8.1.9

Apache Traffic Server 9.0.0 <= 9.2.14

Apache Traffic Server 10.0.0 <= 10.1.3

References

https://lists.apache.org/thread/5prl9glcm9g2swnq9hqxvnoky...
vendor-advisory

CVSS V4

Score:
6.3
Severity:
MEDIUM
Confidentiality:
None
Integrity:
None
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
Physical
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

Omkhar Arasaratnam
Apache Community
.