Apache Traffic Server up to 8.1.9/9.2.14/10.1.3 HPACK Dynamic Table improper synchronization

Summaryinfo

A vulnerability was found in Apache Traffic Server up to 8.1.9/9.2.14/10.1.3. It has been classified as critical. This vulnerability affects unknown code of the component HPACK Dynamic Table. Performing a manipulation results in improper synchronization. This vulnerability was named CVE-2026-65100. The attack may be initiated remotely. There is no available exploit.

Detailsinfo

A vulnerability, which was classified as critical, was found in Apache Traffic Server up to 8.1.9/9.2.14/10.1.3. This affects an unknown code block of the component HPACK Dynamic Table. The manipulation with an unknown input leads to a improper synchronization vulnerability. CWE is classifying the issue as CWE-662. The product utilizes multiple threads or processes to allow temporary access to a shared resource that can only be exclusive to one process at a time, but it does not properly synchronize these actions, which might cause simultaneous accesses of this resource by multiple threads or processes. This is going to have an impact on integrity, and availability. The summary by CVE is:

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.

It is possible to read the advisory at lists.apache.org. This vulnerability is uniquely identified as CVE-2026-65100 since 07/21/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. The technical details are unknown and an exploit is not publicly available. The pricing for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 07/29/2026).

Upgrading to version 9.2.15 or 10.1.4 eliminates this vulnerability.

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Productinfo

Vendor

• Apache

Name

• Traffic Server

Version

• 8.1.0
• 8.1.1
• 8.1.2
• 8.1.3
• 8.1.4
• 8.1.5
• 8.1.6
• 8.1.7
• 8.1.8
• 8.1.9
• 9.2.0
• 9.2.1
• 9.2.2
• 9.2.3
• 9.2.4
• 9.2.5
• 9.2.6
• 9.2.7
• 9.2.8
• 9.2.9
• 9.2.10
• 9.2.11
• 9.2.12
• 9.2.13
• 9.2.14
• 10.1.0
• 10.1.1
• 10.1.2
• 10.1.3

License

• open-source

Website

• Vendor: https://www.apache.org/

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