CVE-2026-23901

What it is

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.

At a glance

Exploitability

Can be exploited locally on the machine with a low-privilege account, but needs a user to act. Limited direct impact.

Exploit odds

0.2% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2026-02-10 10:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-17 10:22 UTC Last updatedMost recent change to the record

Details

Published

2026-02-10 10:15 UTC

Last modified

2026-06-17 10:22 UTC

Exploit probability

0.2% · EPSS, next 30 days

Weakness

CWE-208

Record status

Analyzed

Affected

• Apache Shiro < 2.0.7

Attack profile CVSS 4.0 · 1.0

Attack vector

Local

Complexity

High

Attack requirements

Present

Privileges needed

Low

User interaction

Active

Confidentiality

Low

Integrity

None

Availability

None