CVE-2026-43513

Description

Improper Handling of Case Sensitivity vulnerability in LockOutRealm in Apache Tomcat. This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.21, from 10.1.0-M1 through 10.1.54, from 9.0.0.M1 through 9.0.117, from 8.5.0 through 8.5.100, from 7.0.0 through 7.0.109. Older unsupported versions may also be affected. Users are recommended to upgrade to version 11.0.22, 10.1.55 or 9.0.118 which fix the issue.

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CVSS v3.1 Score

7.5

HIGH

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

EPSS — Exploit Prediction

0.0008

Probability of exploitation

0.24%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-178 CWE-178

Affected Products

Vendor	Product	Versions
apache	tomcat	7.0.0 — 7.0.109
apache	tomcat	8.5.0 — 8.5.100
apache	tomcat	9.0.0 — 9.0.118
apache	tomcat	10.1.0 — 10.1.55
apache	tomcat	11.0.0 — 11.0.22

References

Advisories & Patches

https://lists.apache.org/thread/ytjcgldshj73lcnd1sh95od5hrghwogp

Other References

http://www.openwall.com/lists/oss-security/2026/05/12/9

Frequently Asked Questions

What is CVE-2026-43513? +

Improper Handling of Case Sensitivity vulnerability in LockOutRealm in Apache Tomcat. This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.21, from 10.1.0-M1 through 10.1.54, from 9.0.0.M1 through 9.0.117, from 8.5.0 through 8.5.100, from 7.0.0 through 7.0.109. Older unsupported versions may also be affected. Users are recommended to upgrade to version 11.0.22, 10.1.55 or 9.0.118 which fix the issue. It has a CVSS v3.1 base score of 7.5 (HIGH).

How severe is CVE-2026-43513? +

CVE-2026-43513 has a CVSS v3.1 score of 7.5 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0008, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-43513? +

CVE-2026-43513 affects products from apache, specifically: tomcat. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-43513? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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