CVE-2026-77756

Apache Tomcat: Transfer-Encoding honored for HTTP/1.0 requests

Published: Sep 23, 2026Updated: Sep 23, 2026 Sources: CVE List NVDCWE-444

3.7LOW

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.

No summary for this CVE yet.

CVSS Vector Breakdown

Exploitability

AV:NAttack Vector

Network

AC:HAttack Complexity

High

PR:NPrivileges Required

None

UI:NUser Interaction

None

Scope

S:UScope

Unchanged

Impact

C:NConfidentiality

None

I:NIntegrity

None

A:LAvailability

Low

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Weaknesses

CWE-444

Affected Products

Apache Software Foundation

oss-project·USaka apache foundation

Apache TomcatOn-premWeb App

Networking Infrastructure / load-balancer-proxy

Exploitability

No known exploits, KEV entries, or remediation guidance available for this vulnerability yet.

Attack Graph

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MITRE ATT&CK

1 technique

Collection

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References

https://lists.apache.org/thread/bl5b6rxqh3vb2k9bj2794vhor7o6xl3z

lists.apache.org

http://www.openwall.com/lists/oss-security/2026/09/23/22

openwall.com

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