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CVE-2026-86350: CWE-444 Inconsistent interpretation of HTTP requests ('HTTP Request/Response smuggling') in Apache Software Foundation Apache Tomcat

0
Critical
VulnerabilityCVE-2026-86350cvecve-2026-86350cwe-444
Published: 09/23/2026 (09/23/2026, 11:31:36 UTC)
Source: CVE Database V5
Vendor/Project: Apache Software Foundation
Product: Apache Tomcat

Description

Inconsistent interpretation of HTTP/2 requests ('HTTP Request/Response smuggling') vulnerability in Apache Tomcat caused by a regression in fix for CVE-2026-41293 can trigger request header mix-up. This issue affects Apache Tomcat: from 11.0.22 through 11.0.25, from 10.1.55 through 10.1.59, from 9.0.118 through 9.0.121. Users are recommended to upgrade to version 11.0.26, 10.1.60 or 9.0.122, which fix the issue.

CVSS v3.1

Score 9.1critical

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Affected software

Apache Software Foundation

Apache Tomcat

Affected versions
>=11.0.22 <=11.0.25>=10.1.55 <=10.1.59>=9.0.118 <=9.0.121
Mavenmore threats →ai
org.apache.tomcat/tomcat
pkg:maven/org.apache.tomcat/tomcat
Affected versions
>=9.0.118 <=9.0.121

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AI-Powered Analysis

Machine-generated threat intelligence

AILast updated: 09/23/2026, 12:02:58 UTC

Technical Analysis

CVE-2026-86350 is a security vulnerability in Apache Tomcat where inconsistent interpretation of HTTP/2 requests can cause HTTP Request/Response smuggling due to a regression in the fix for CVE-2026-41293. This results in request header mix-ups that may impact the integrity of HTTP communications. The vulnerability affects multiple Apache Tomcat branches: 9.0.118 to 9.0.121, 10.1.55 to 10.1.59, and 11.0.22 to 11.0.25. The issue is resolved in versions 9.0.122, 10.1.60, and 11.0.26.

Potential Impact

The vulnerability allows inconsistent parsing of HTTP/2 requests, which can lead to HTTP Request/Response smuggling attacks. This can cause request header mix-ups, potentially impacting the security and reliability of HTTP communications handled by affected Apache Tomcat servers. No known exploits in the wild have been reported at this time.

Mitigation Recommendations

Users should upgrade affected Apache Tomcat versions to 9.0.122, 10.1.60, or 11.0.26, where the vulnerability has been fixed. Applying these official updates is the recommended remediation.

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Technical Details

Data Version
5.2
Assigner Short Name
apache
Date Reserved
2026-09-07T09:49:48.382Z
State
PUBLISHED

Threat ID: 6ab3bc94f7a7c54106b7b02a

Added to database: 09/23/2026, 11:48:36 UTC

Last enriched: 09/23/2026, 12:02:58 UTC

Last updated: 09/24/2026, 03:22:47 UTC

Views: 13

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