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High severity · published Oct 21, 2026
CVE-2025-55702
Apache Traffic Server: An unread Expect: 100-continue request body is framed as a new request
New
8.7
CVSS
0.3%
EPSS
No
On KEV
Description
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.
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N
Attack vector
Network
Complexity
High
Privileges
None
User interaction
None
Confidentiality
High
Integrity
High
Availability
None
Scope
Changed
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 25% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
AT
Apache Traffic Server · Apache Software Foundation
8.0.0 through 8.1.11; 9.0.0 through 9.2.15; 10.0.0 through 10.1.4; 10.2.0 · source: vendor
Affected product
AT
Apache Traffic Server
Apache Software Foundation
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2025-55702
CVE.org
https://www.cve.org/CVERecord?id=CVE-2025-55702
lists.apache.org
https://lists.apache.org/thread/r95dq29ywcd1f4x30snxlqmb12z4s4kc
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