Apache Traffic Server 8-10.2.0 Vulnerable to 100-continue Request Smuggling
CVE-2025-55702 Published on October 21, 2026
Apache Traffic Server: An unread Expect: 100-continue request body is framed as a new request
When a client sends a POST with Expect: 100-continue and the origin answers before reading the body, Apache Traffic Server parses the unread body left on the client connection as the next request. An attacker behind a front-end proxy that shares connections to Traffic Server can use this to smuggle requests past the front end and desynchronize responses for other users.
This issue affects Apache Traffic Server: from 8.0.0 through 8.1.11, from 9.0.0 through 9.2.15, from 10.0.0 through 10.1.4, 10.2.0.
Users are recommended to upgrade to version 9.2.16, 10.1.5, or 10.2.1, which fix the issue.
Vulnerability Analysis
CVE-2025-55702 is exploitable with network access, and does not require authorization privileges or user interaction. This vulnerability is consided to have a high level of attack complexity. The potential impact of an exploit of this vulnerability is considered to have a high impact on confidentiality and integrity, and no impact on availability.
Weakness Type
What is a HTTP Request Smuggling Vulnerability?
When malformed or abnormal HTTP requests are interpreted by one or more entities in the data flow between the user and the web server, such as a proxy or firewall, they can be interpreted inconsistently, allowing the attacker to "smuggle" a request to one device without the other device being aware of it.
CVE-2025-55702 has been classified to as a HTTP Request Smuggling vulnerability or weakness.
Products Associated with CVE-2025-55702
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Affected Versions
Apache Software Foundation Apache Traffic Server:- Version 8.0.0, <= 8.1.11 is affected.
- Version 9.0.0, <= 9.2.15 is affected.
- Version 10.0.0, <= 10.1.4 is affected.
- Version 10.2.0 is affected.