Is CVE-2026-23903 in the CISA KEV catalog?

No. CVE-2026-23903 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-23903?

CVE-2026-23903 has a CVSS v3 base score of 5.3 (MEDIUM).

What is the EPSS score for CVE-2026-23903?

CVE-2026-23903 has an EPSS score of 0.36% (28th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2026-23903?

Upgrade shiro to 2.0.7 or later.

CVE & CISA-KEV Catalog

CVE-2026-23903

MEDIUM

5.3

CVSS v3

NVD

Description

Authentication Bypass by Alternate Name vulnerability in Apache Shiro. This issue affects Apache Shiro: before 2.0.7. Users are recommended to upgrade to version 2.0.7, which fixes the issue. The issue only effects static files. If static files are served from a case-insensitive filesystem, such as default macOS setup, static files may be accessed by varying the case of the filename in the request. If only lower-case (common default) filters are present in Shiro, they may be bypassed this way. Shiro 2.0.7 and later has a new parameters to remediate this issue shiro.ini: filterChainResolver.caseInsensitive = true application.propertie: shiro.caseInsensitive=true Shiro 3.0.0 and later (upcoming) makes this the default.

CWE-289

How to fix

Remediation Available

shiroNVD

Affected:< 2.0.7Fixed in:2.0.7CVE-2026-23903derived from NVD

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

ConfidentialityLow

IntegrityNone

AvailabilityNone

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

Exploit Intelligence

0.36%probability of exploitation in 30 days

28thpercentile

Low risk: more likely to be exploited than 28% of all known CVEs.

References

Vendor Advisory1

lists.apache.org

Third-Party Advisory1

openwall.com

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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 2026-02-11.