Advisory severityLow3.7Apache Software Foundation

Low [CVE-2026-77756] 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 low-severity Apache Software Foundation advisory covers CVE-2026-77756 affecting Apache Tomcat.

Aggregated and source-linked by VulniPulse. Data sources, validation and limitations.

CVE-2026-77756 Source published Sep 23, 2026Source updated Sep 23, 2026

VulniPulse record published Sep 23, 2026Record updated Sep 23, 2026

CVE-2026-77756

Affected products & platforms

Apache Software FoundationTomcat

Open source advisory

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Summary

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.

Affected versions

11.0.0-M1 through 11.0.25
10.1.0-M1 through 10.1.59
9.0.47 through 9.0.121.
8.5.67 through 8.5.100.
through 9.0.121
through 8.5.100

Official advisory · high-confidence parse· fetched 13 days ago·verify at source

Fixed versions

11.0.26
10.1.60
9.0.122

Official advisory · high-confidence parse· fetched 13 days ago·verify at source

Mitigation checklist

Recommended fix / mitigation

Users are recommended to upgrade to version 11.0.26, 10.1.60 or 9.0.122, which fix the issue.

Official advisory · high-confidence parse· fetched 13 days ago·verify at source

Sources

Official and corroborating records used to build this advisory.

Official vendor advisoryofficial
Official advisory page fetched and parsed; accepted detail fields are attributed to this page.
Apache Software Foundation
CVE.org CNA recordCVE.org
Independent CNA record used for near-real-time discovery and missed-CVE reconciliation. Discovered from the machine-readable feed https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/delta.json; this link opens the CVE.org record for CVE-2026-77756 instead of the raw feed document.
CVE Program

Cross-references

Validate CVE metadata against the authoritative registries.

CVE-2026-77756NVD CVE.org MITRE

Official resources

Apache Tomcat security bulletins (per major version) (target: 11.0.26 / 10.1.60 / 9.0.122)
Official documentation
This advisory names 11.0.26 / 10.1.60 / 9.0.122 as the first fixed releases — official upgrade documentation for Apache Tomcat security bulletins (per major version).
ASF Security — reporting & CVE process
Official documentation
The Apache Software Foundation's official security page: how ASF CVEs are published and where each project's advisories live.
Apache project downloads (fixed releases)
Official documentation
Official ASF download tree — fetch the fixed release named in this advisory from the project's directory.

Discussion(0)

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