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High severity · published Aug 25, 2026
CVE-2026-66422
Apache Tomcat: Servlet role references can bypass declarative role constraints
8.1
CVSS
0.4%
EPSS
No
On KEV
Description
Improper Authorization vulnerability in Apache Tomcat cause by security-role-ref definitions being incorrectly used as role aliases within the Realm in additional to the correct usage with Request.isUserInRole(). This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.24, from 10.1.0-M1 through 10.1.57, from 9.0.25 through 9.0.120. The following versions were EOL at the time the CVE was created but are known to be affected: from 8.5.46 through 8.5.100, from 7.0.97 through 7.0.109. Other unsupported versions may also be affected. Users are recommended to upgrade to version 11.0.25, 10.1.58 or 9.0.121, which fix the issue.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
None
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 37% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
TO
Tomcat · Apache
11.0.0-M1 through 11.0.24; 10.1.0-M1 through 10.1.57; 9.0.25 through 9.0.120; 8.5.46 through 8.5.100; 7.0.97 through 7.0.109 · source: vendor, NVD
Affected product
TO
Tomcat
Apache
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-66422
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-66422
Vendor Advisory
https://lists.apache.org/thread/j5plylz1b2vhqvbkqn7k58nygxhcpk73
Third Party Advisory
http://www.openwall.com/lists/oss-security/2026/08/26/6
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