How severe is CVE-2026-23903?

CVE-2026-23903 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability none.

Is CVE-2026-23903 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (28th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-23903?

CVE-2026-23903 affects Apache Shiro. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-23903?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-23903 have an EU (EUVD) identifier?

Yes. CVE-2026-23903 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-6903.

When was CVE-2026-23903 published?

CVE-2026-23903 was published on 2026-02-09 and last updated on 2026-06-17.

CVE-2026-23903

CVE-2026-23903 is a medium-severity vulnerability in Apache Shiro with a CVSS 3.x base score of 5.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-289.

Key facts

Severity: Medium (CVSS 3.x base score 5.3)
EPSS exploit prediction: 0% (28th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-6903
Weakness: CWE-289
Affected product: Apache Shiro
Published: 2026-02-09
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2026-23903?: 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.
How severe is CVE-2026-23903?: CVE-2026-23903 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability none.
Is CVE-2026-23903 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (28th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-23903?: CVE-2026-23903 affects Apache Shiro. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-23903?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-23903 have an EU (EUVD) identifier?: Yes. CVE-2026-23903 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-6903.
When was CVE-2026-23903 published?: CVE-2026-23903 was published on 2026-02-09 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:apache:shiro:*:*:*:*:*:*:*:*

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