Apache Tomcat: Transfer-Encoding honored for HTTP/1.0 requests (CVE-2026-77756) | HOL Guard CVE

Unknown severity · Source severity not reportedCVE-2026-77756

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

Answer in brief

CVE-2026-77756 records a Unknown severity vulnerability in Apache Tomcat: Transfer-Encoding honored for HTTP/1.0 requests. The current sources do not mark it as known exploited. The current feed maps Apache Software Foundation/Apache Tomcat (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Sep 23, 2026Updated Sep 23, 2026Source checked Sep 23, 2026First seen by HOL Sep 23, 2026Material review Sep 23, 2026

Upstream Advisory

Key facts

Risk: Unknown severitySource severity not reported
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Not reported

Why this deserves its current priority

A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps Apache Software Foundation/Apache Tomcat (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
Apache Software Foundation/Apache Tomcatgeneric	>=11.0.0-M1 <=11.0.25 \|\| >=10.1.0-M1 <=10.1.59 \|\| >=9.0.47 <=9.0.121 \|\| >=8.5.67 <=8.5.100	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for Apache Software Foundation/Apache Tomcat.
Review the reported fix. Monitor this advisory for an available fix and review any installs of the affected package.

Evidence timeline and material changes

Published upstream
Sep 23, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 23, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Sep 23, 2026

Sources and claim methodology

Source referencelists.apache.org

Upstream source 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.

Quoted source text, attributed separately from HOL analysis.