CVE-2026-66422

HIGH 8.1

Published 2026-08-25 · Last modified 2026-08-26

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.

ELEVATED IMPACT

Severe if exploited (CVSS 8.1), but no known exploitation and low modeled probability. Patch on a normal cadence.

Exploitation likelihood

0.6%chance of exploitation in 30 days · 45th percentile

○ In CISA KEV ○ Public exploit / PoC

Impact if exploited

8.1CVSS 3.1 · HIGH

ConfidentialityNone
IntegrityHigh
AvailabilityHigh

What an attacker needs

✓Access: Reachable over the network — no local access needed
⚠Privileges: Requires a low-privilege account
✓User interaction: No user interaction needed
✓Complexity: No special conditions — reliably repeatable

✓ lowers the bar for an attacker · ⚠ raises it

Proof of concept & exploit code

github-search Search GitHub for public PoC repos

Test against your own equipment

curl -s https://vulnpedia.com/cve/CVE-2026-66422/poc.jsonMachine-readable PoC index for this CVE (for automation).

Listed for defensive triage, patch verification, and authorized testing on systems you own. Machine-readable: /cve/CVE-2026-66422/poc.json

Affected

Vendors Apache Software Foundation Apache

Products Apache Tomcat Tomcat

Weakness (CWE)

CWE-285: Improper Authorization

CVSS vector

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

Known Affected Software Configurations

Vendor	Product	Version range
Apache	Tomcat	≥ 7.0.97 and ≤ 7.0.109
Apache	Tomcat	≥ 8.5.46 and < 9.0.121
Apache	Tomcat	≥ 10.1.0 and < 10.1.58
Apache	Tomcat	≥ 11.0.0 and < 11.0.25

All CVSS metrics

HIGH 8.1 v3.1 · ADP Primary
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H
HIGH 8.1 v3.1 · NVD Secondary
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H

References

Advisories

https://lists.apache.org/thread/j5plylz1b2vhqvbkqn7k58nygxhcpk73 vendor-advisoryVendor AdvisoryMailing List
http://www.openwall.com/lists/oss-security/2026/08/26/6 Third Party AdvisoryMailing List

Sources: NVD · CVE.org · EPSS