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Posted to dev@tomcat.apache.org by Mark Thomas <ma...@apache.org> on 2026/09/23 10:01:38 UTC
[SECURITY] CVE-2026-77756 Apache Tomcat - Transfer-Encoding honored for HTTP/1.0 requests
CVE-2026-77756 Apache Tomcat - Transfer-Encoding honored for HTTP/1.0
requests
Severity: Low
Vendor: The Apache Software Foundation
Versions Affected:
Apache Tomcat 11.0.0-M1 to 11.0.25
Apache Tomcat 10.1.0-M1 to 10.1.59
Apache Tomcat 9.0.47 to 9.0.121
Description:
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.
Mitigation:
Users of the affected versions should apply one of the following
mitigations:
- Remove the examples web application
- Upgrade to Apache Tomcat 11.0.26
- Upgrade to Apache Tomcat 10.1.60
- Upgrade to Apache Tomcat 9.0.122
History:
2026-09-23 Original advisory
References:
[1] https://tomcat.apache.org/security-11.html
[2] https://tomcat.apache.org/security-10.html
[3] https://tomcat.apache.org/security-9.html
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[UPDATE][SECURITY] CVE-2026-77756 Apache Tomcat - Transfer-Encoding honored for HTTP/1.0 requests
Posted by Mark Thomas via dev <de...@tomcat.apache.org>.
CVE-2026-77756 Apache Tomcat - Transfer-Encoding honored for HTTP/1.0
requests
Severity: Low
Vendor: The Apache Software Foundation
Versions Affected:
Apache Tomcat 11.0.0-M1 to 11.0.25
Apache Tomcat 10.1.0-M1 to 10.1.59
Apache Tomcat 9.0.47 to 9.0.121
Description:
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.
Mitigation:
Users of the affected versions should apply one of the following
mitigations:
- Upgrade to Apache Tomcat 11.0.26
- Upgrade to Apache Tomcat 10.1.60
- Upgrade to Apache Tomcat 9.0.122
History:
2026-09-28 Correction. Removing the examples app is not a mitigation
2026-09-23 Original advisory
References:
[1] https://tomcat.apache.org/security-11.html
[2] https://tomcat.apache.org/security-10.html
[3] https://tomcat.apache.org/security-9.html
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To unsubscribe, e-mail: dev-unsubscribe@tomcat.apache.org
For additional commands, e-mail: dev-help@tomcat.apache.org
[UPDATE][SECURITY] CVE-2026-77756 Apache Tomcat - Transfer-Encoding honored for HTTP/1.0 requests
Posted by Mark Thomas <ma...@apache.org>.
CVE-2026-77756 Apache Tomcat - Transfer-Encoding honored for HTTP/1.0
requests
Severity: Low
Vendor: The Apache Software Foundation
Versions Affected:
Apache Tomcat 11.0.0-M1 to 11.0.25
Apache Tomcat 10.1.0-M1 to 10.1.59
Apache Tomcat 9.0.47 to 9.0.121
Description:
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.
Mitigation:
Users of the affected versions should apply one of the following
mitigations:
- Upgrade to Apache Tomcat 11.0.26
- Upgrade to Apache Tomcat 10.1.60
- Upgrade to Apache Tomcat 9.0.122
History:
2026-09-28 Correction. Removing the examples app is not a mitigation
2026-09-23 Original advisory
References:
[1] https://tomcat.apache.org/security-11.html
[2] https://tomcat.apache.org/security-10.html
[3] https://tomcat.apache.org/security-9.html
---------------------------------------------------------------------
To unsubscribe, e-mail: dev-unsubscribe@tomcat.apache.org
For additional commands, e-mail: dev-help@tomcat.apache.org
[UPDATE][SECURITY] CVE-2026-77756 Apache Tomcat - Transfer-Encoding honored for HTTP/1.0 requests
Posted by Mark Thomas <ma...@apache.org>.
CVE-2026-77756 Apache Tomcat - Transfer-Encoding honored for HTTP/1.0
requests
Severity: Low
Vendor: The Apache Software Foundation
Versions Affected:
Apache Tomcat 11.0.0-M1 to 11.0.25
Apache Tomcat 10.1.0-M1 to 10.1.59
Apache Tomcat 9.0.47 to 9.0.121
Description:
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.
Mitigation:
Users of the affected versions should apply one of the following
mitigations:
- Upgrade to Apache Tomcat 11.0.26
- Upgrade to Apache Tomcat 10.1.60
- Upgrade to Apache Tomcat 9.0.122
History:
2026-09-28 Correction. Removing the examples app is not a mitigation
2026-09-23 Original advisory
References:
[1] https://tomcat.apache.org/security-11.html
[2] https://tomcat.apache.org/security-10.html
[3] https://tomcat.apache.org/security-9.html
[UPDATE][SECURITY] CVE-2026-77756 Apache Tomcat - Transfer-Encoding honored for HTTP/1.0 requests
Posted by Mark Thomas <ma...@apache.org>.
CVE-2026-77756 Apache Tomcat - Transfer-Encoding honored for HTTP/1.0
requests
Severity: Low
Vendor: The Apache Software Foundation
Versions Affected:
Apache Tomcat 11.0.0-M1 to 11.0.25
Apache Tomcat 10.1.0-M1 to 10.1.59
Apache Tomcat 9.0.47 to 9.0.121
Description:
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.
Mitigation:
Users of the affected versions should apply one of the following
mitigations:
- Upgrade to Apache Tomcat 11.0.26
- Upgrade to Apache Tomcat 10.1.60
- Upgrade to Apache Tomcat 9.0.122
History:
2026-09-28 Correction. Removing the examples app is not a mitigation
2026-09-23 Original advisory
References:
[1] https://tomcat.apache.org/security-11.html
[2] https://tomcat.apache.org/security-10.html
[3] https://tomcat.apache.org/security-9.html
---------------------------------------------------------------------
To unsubscribe, e-mail: users-unsubscribe@tomcat.apache.org
For additional commands, e-mail: users-help@tomcat.apache.org
[UPDATE][SECURITY] CVE-2026-77756 Apache Tomcat - Transfer-Encoding honored for HTTP/1.0 requests
Posted by Mark Thomas via users <us...@tomcat.apache.org>.
CVE-2026-77756 Apache Tomcat - Transfer-Encoding honored for HTTP/1.0
requests
Severity: Low
Vendor: The Apache Software Foundation
Versions Affected:
Apache Tomcat 11.0.0-M1 to 11.0.25
Apache Tomcat 10.1.0-M1 to 10.1.59
Apache Tomcat 9.0.47 to 9.0.121
Description:
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.
Mitigation:
Users of the affected versions should apply one of the following
mitigations:
- Upgrade to Apache Tomcat 11.0.26
- Upgrade to Apache Tomcat 10.1.60
- Upgrade to Apache Tomcat 9.0.122
History:
2026-09-28 Correction. Removing the examples app is not a mitigation
2026-09-23 Original advisory
References:
[1] https://tomcat.apache.org/security-11.html
[2] https://tomcat.apache.org/security-10.html
[3] https://tomcat.apache.org/security-9.html
---------------------------------------------------------------------
To unsubscribe, e-mail: users-unsubscribe@tomcat.apache.org
For additional commands, e-mail: users-help@tomcat.apache.org
[UPDATE][SECURITY] CVE-2026-77756 Apache Tomcat - Transfer-Encoding honored for HTTP/1.0 requests
Posted by Mark Thomas <ma...@apache.org>.
CVE-2026-77756 Apache Tomcat - Transfer-Encoding honored for HTTP/1.0
requests
Severity: Low
Vendor: The Apache Software Foundation
Versions Affected:
Apache Tomcat 11.0.0-M1 to 11.0.25
Apache Tomcat 10.1.0-M1 to 10.1.59
Apache Tomcat 9.0.47 to 9.0.121
Description:
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.
Mitigation:
Users of the affected versions should apply one of the following
mitigations:
- Upgrade to Apache Tomcat 11.0.26
- Upgrade to Apache Tomcat 10.1.60
- Upgrade to Apache Tomcat 9.0.122
History:
2026-09-28 Correction. Removing the examples app is not a mitigation
2026-09-23 Original advisory
References:
[1] https://tomcat.apache.org/security-11.html
[2] https://tomcat.apache.org/security-10.html
[3] https://tomcat.apache.org/security-9.html