CVE-2026-65100

Apache Traffic Server: HPACK encoder desynchronizes from the decoder after a failed header encode

MEDIUM
4.8
CVSS Score
Published: July 29, 2026 at 09:06 AM UTC
Updated: October 1, 2026 at 06:17 PM UTC
1 product affected across 1 vendorTraffic Server

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Severity
MEDIUM4.8
Exploit prediction
EPSS 0.6%
SSVC
No known exploit

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 8.1.9, 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

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

10.0.0 ≤ v ≤ 10.1.310.0.0 ≤ v < 10.1.48.0.0 ≤ v ≤ 8.1.118.0.0 ≤ v ≤ 8.1.99.0.0 ≤ v ≤ 9.2.149.0.0 ≤ v < 9.2.1510.0.08.0.09.0.0
Affected range stops below 10.1.4, so it looks safe — our inference, not a vendor statement
Affected range stops below 9.2.15, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (1)

Vendor AdvisoryMailing List
Source: cverecord
https://lists.apache.org/thread/5prl9glcm9g2swnq9hqxvnokylm1gr6d

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

4.8MEDIUMapache
Attack Vector
NETWORK
Complexity
HIGH
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
LOW
Availability
LOW
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-696

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