CVE-2026-23903 | Apache Shiro: Auth bypass when accessing static files only on case-insensitive filesystems

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.

Published: 2026-02-09 Last update: 2026-06-17 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-23903 is rated Low Risk (31.3/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.36%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-23903

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.06% 0.36% +0.30%
2 2026-02-10 0.04% 0.06% +0.02%
3 2026-02-09 — 0.04% —

Full EPSS history (3 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-23903

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.3 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
 3.9 1.4 134c704f-9b21-4f2e-91b3-4a467353bcc0

Weakness enumeration for CVE-2026-23903

GitHub Security Advisory for CVE-2026-23903

GHSA-c244-p6m5-vqj6 · Severity: medium · Ecosystem: maven — Apache Shiro has an Authentication Bypass

OS Trackers for CVE-2026-23903

vendor priority summary link
debian not yet assigned CVE-2026-23903 not yet assigned priority: Debian including 1 source packages (shiro), 4 status rows across 4 suites (bookworm, bullseye, sid, trixie): open 4. https://security-tracker.debian.org/tracker/CVE-2026-23903
redhat medium — https://access.redhat.com/security/cve/CVE-2026-23903
ubuntu medium CVE-2026-23903 medium priority: Ubuntu including 1 source packages (shiro), 7 status rows across 7 suites (bionic, focal, jammy, noble, questing, upstream, xenial): needs-triage 7. https://ubuntu.com/security/CVE-2026-23903

Affected software / configurations for CVE-2026-23903

Vendor Product Version Raw CPE
apache shiro < 2.0.7 cpe:2.3:a:apache:shiro:*:*:*:*:*:*:*:*

References for CVE-2026-23903

cvelogic Threat Intelligence