Is CVE-2026-55276 in the CISA KEV catalog?

No. CVE-2026-55276 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-55276?

CVE-2026-55276 has a CVSS v3 base score of 9.1 (CRITICAL).

What is the EPSS score for CVE-2026-55276?

CVE-2026-55276 has an EPSS score of 0.29% (20th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2026-55276?

Upgrade tomcat10 on rhel 8 to main@noarch or later. Fixes are available for 4 affected products.

CVE & CISA-KEV Catalog

CVE-2026-55276

CRITICAL

9.1

CVSS v3

NVD

Description

Always-Incorrect Control Flow Implementation vulnerability in Apache Tomcat meant that special roles and empty authorisation constraints were not included when the effective web.xml was logged. This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.22, from 10.1.0-M1 through 10.1.55, from 9.0.0.M1 through 9.0.118, from 8.5.0 through 8.5.100. Other versions that have reached end of support may also be affected. Users are recommended to upgrade to version 11.0.23, 10.1.56 or 9.0.119 which fixes the issue.

CWE-670

How to fix

Remediation Available

tomcat10Red Hat / RHEL

Fixed in:main@noarchRHSA-2026:29203

Fixed in:main@srcRHSA-2026:29203

tomcat10Rocky

Fixed in:main@noarchRHSA-2026:29203

Fixed in:main@srcRHSA-2026:29203

tomcat11Red Hat / RHEL

Fixed in:main@noarchRHSA-2026:32960

Fixed in:main@srcRHSA-2026:32960

tomcat11Rocky

Fixed in:main@noarchRHSA-2026:32960

Fixed in:main@srcRHSA-2026:32960

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityNone

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

Exploit Intelligence

0.29%probability of exploitation in 30 days

20thpercentile

Low risk: more likely to be exploited than 20% of all known CVEs.

References

Other references2

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-06-30.