Vulnerability in Apache Shiro
CVE-2026-23901
Observable Timing Discrepancy vulnerability in Apache Shiro. This issue affects Apache Shiro: from 1.*, 2.* before 2.0.7. Users are recommended to upgrade to version 2.0.7 or later, which fixes the issue. Prior to Shiro 2.0.7, code paths for non-existent vs. existing users are different enough, that a brute-force attack may be able to tell, by timing the requests only, determine if the request failed because of a non-existent user vs. wrong password. The most likely attack vector is a local attack only. Shiro security model https://shiro.apache.org/security-model.html#username_enumeration discusses this as well. Typically, brute force attack can be mitigated at the infrastructure level.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 2.5 (Low). Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N.
EPSS exploit prediction
EPSS: 0.002 (11.6th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 12th percentile — 11.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: +0.000
Affected products
- Apache Shiro
- Apache Software Foundation Shiro — versions 0
Weakness classification (CWE)
References
- lists.apache.org/thread/mm1jct9b86jvnh3y44tj22xvjtx3xhhh (vendor-advisory, Mailing List, Third Party Advisory, Issue Tracking)
- af854a3a-2127-422b-91ae-364da2661108 (Mailing List, Third Party Advisory)
Frequently asked questions
- What is CVE-2026-23901?
- CVE-2026-23901 is a low-severity vulnerability in Apache Shiro, classified under CWE-208. CVSS score: 2.5/10. Published 2026-02-10.
- How severe is CVE-2026-23901?
- Low severity. CVSS v3 base score is 2.5 out of 10.