CVE-2026-77756

low

Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') vulnerability in Apache Tomcat caused by processing the transfer-encoding head…

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

3.7

3.7 (CVSS v3.1)

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L

Severity source: NVD CVSS v3.1 (134c704f-9b21-4f2e-91b3-4a467353bcc0)

Timeline (UTC)

Published: 2026-09-23 12:17

Modified: 2026-09-23 19:19

NVD status: Awaiting Analysis

Last synced 3 days ago

Verified against the source API 2026-10-27 06:55 UTC

Exploitation

Not listed in CISA KEV (as of last catalog sync)

Absence from KEV does not mean a CVE is not exploited. Exploitation status: unknown (no authoritative evidence in our sources).

Affected products

Not reported by the source (unknown — not "none").

Weakness classification (CWE)

CWE-444

Source: NVD / CISA. “NVD-CWE-Other” and “NVD-CWE-noinfo” mean NVD could not assign a specific weakness.

Mitigation & advisories

No vendor advisory or patch reference tagged by NVD. Check the references below.

References

https://lists.apache.org/thread/bl5b6rxqh3vb2k9bj2794vhor7o6xl3z security@apache.org
http://www.openwall.com/lists/oss-security/2026/09/23/22 af854a3a-2127-422b-91ae-364da2661108

Data sources

NVD CVE API 2.0 — fetched 2026-10-27 06:55 UTC · record ↗

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