CVE-2026-77756: CWE-444 Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') in Apache Software Foundation Apache Tomcat
Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') vulnerability in Apache Tomcat caused by processing the transfer-encoding header for an HTTP/1.0 request may allow an attacker to cause one request from another user to fail when Tomcat is located behind a reverse proxy. This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.25, from 10.1.0-M1 through 10.1.59, from 9.0.47 through 9.0.121. The following versions were EOL at the time the CVE was created but are known to be affected: from 8.5.67 through 8.5.100. Other unsupported versions may also be affected. Users are recommended to upgrade to version 11.0.26, 10.1.60 or 9.0.122, which fix the issue.
AI Analysis
Technical Summary
This vulnerability in Apache Tomcat arises from inconsistent processing of the transfer-encoding header in HTTP/1.0 requests, leading to HTTP request/response smuggling. An attacker may exploit this to cause a request from another user to fail when Tomcat is deployed behind a reverse proxy. Affected versions include 11.0.0-M1 through 11.0.25, 10.1.0-M1 through 10.1.59, 9.0.47 through 9.0.121, and 8.5.67 through 8.5.100 (EOL). The Apache Software Foundation recommends upgrading to versions 11.0.26, 10.1.60, or 9.0.122 to remediate the issue.
Potential Impact
An attacker exploiting this vulnerability can cause denial of service for other users' requests by manipulating HTTP request parsing behind a reverse proxy. There is no indication of remote code execution or data leakage in the provided data. The impact is primarily denial of service or request disruption.
Mitigation Recommendations
Users should upgrade affected Apache Tomcat versions to 11.0.26, 10.1.60, or 9.0.122, which contain fixes for this vulnerability. No other mitigation steps are indicated. Patch status is confirmed by the vendor advisory.
CVE-2026-77756: CWE-444 Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') in Apache Software Foundation Apache Tomcat
Description
Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') vulnerability in Apache Tomcat caused by processing the transfer-encoding header for an HTTP/1.0 request may allow an attacker to cause one request from another user to fail when Tomcat is located behind a reverse proxy. This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.25, from 10.1.0-M1 through 10.1.59, from 9.0.47 through 9.0.121. The following versions were EOL at the time the CVE was created but are known to be affected: from 8.5.67 through 8.5.100. Other unsupported versions may also be affected. Users are recommended to upgrade to version 11.0.26, 10.1.60 or 9.0.122, which fix the issue.
CVSS v3.1
Score 3.7low
Affected software
Apache Software Foundation
Apache Tomcat
pkg:maven/org.apache.tomcat/tomcatRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
This vulnerability in Apache Tomcat arises from inconsistent processing of the transfer-encoding header in HTTP/1.0 requests, leading to HTTP request/response smuggling. An attacker may exploit this to cause a request from another user to fail when Tomcat is deployed behind a reverse proxy. Affected versions include 11.0.0-M1 through 11.0.25, 10.1.0-M1 through 10.1.59, 9.0.47 through 9.0.121, and 8.5.67 through 8.5.100 (EOL). The Apache Software Foundation recommends upgrading to versions 11.0.26, 10.1.60, or 9.0.122 to remediate the issue.
Potential Impact
An attacker exploiting this vulnerability can cause denial of service for other users' requests by manipulating HTTP request parsing behind a reverse proxy. There is no indication of remote code execution or data leakage in the provided data. The impact is primarily denial of service or request disruption.
Mitigation Recommendations
Users should upgrade affected Apache Tomcat versions to 11.0.26, 10.1.60, or 9.0.122, which contain fixes for this vulnerability. No other mitigation steps are indicated. Patch status is confirmed by the vendor advisory.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- apache
- Date Reserved
- 2026-08-21T09:55:42.227Z
- State
- PUBLISHED
Threat ID: 6ab3b90ff7a7c54106b30f1c
Added to database: 09/23/2026, 11:33:35 UTC
Last enriched: 09/23/2026, 11:48:10 UTC
Last updated: 09/24/2026, 03:00:14 UTC
Views: 20
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