Medium severity · published Feb 9, 2026
CVE-2026-23903
Apache Shiro: Auth bypass when accessing static files only on case-insensitive filesystems
5.3
CVSS
0.4%
EPSS
No
On KEV
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 2.1.0 and later has a new parameters to remediate this issue
shiro.ini: filterChainResolver.caseInsensitive = true
application.properties: shiro.caseInsensitive=true
Shiro 3.0.0 and later makes this the default in shiro.ini-based configurations.
Shiro 3.0.1 and later makes this the default in all configurations, including programmatic and Spring / Spring Boot.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
Low
Integrity
None
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 34% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
AS
Apache Shiro · Apache Software Foundation
before 2.0.7 · source: vendor
SH
Shiro · Apache
before 2.0.7 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-23903
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-23903
Mailing List
https://lists.apache.org/thread/5jjf0hnjcol58z2m5y255c7scz1lnp8k
Mailing List
http://www.openwall.com/lists/oss-security/2026/02/08/1
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