Critical severity · published Sep 23, 2026
CVE-2026-86350
Apache Tomcat: Regression in fix for CVE-2026-41293 can trigger request header mix-up
9.1
CVSS
0.5%
EPSS
No
On KEV
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 vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
High
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.5% · higher than 41% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
TO
Tomcat · Apache
11.0.22 through 11.0.25; 10.1.55 through 10.1.59; 9.0.118 through 9.0.121 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-86350
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-86350
lists.apache.org
https://lists.apache.org/thread/mss45z99lcdd5dtpgcn45dy82f3toswc
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