Apache Shiro: Brute force attack possible to determine valid user...

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LOW

CVSS:4.0/AV:L/AC:H/AT:P/PR:L/UI:A/VC:L/VI:N/VA:N/SC:L/SI:N/SA:N/S:N/AU:Y/R:A/V:C/RE:L/U:Green

Description

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.

Basic Information

ID CVE-2026-23901

Source apache

Published Feb 10, 2026 at 09:25

Modified Feb 10, 2026 at 10:22

Affected Product

Vendor Apache Software Foundation

Product Apache Shiro

Affected Versions Apache Software Foundation Apache Shiro 0

CWE Classification

CWE-208

References

lists.apache.org /thread/mm1jct9b86jvnh3y44tj22xvjtx3xhhh

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    "published": "2026-02-10T09:25:51.765Z",
    "modified": "2026-02-10T10:22:44.721Z",
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Apache Shiro: Brute force attack possible to determine valid user names_CVE-2026-23901