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Vulnerability · Published Jun 25, 2026 · Assigned by apache

CVE-2026-56091Apache Shiro: Authentication bypass in Guice-Web integration

High 8.2

In plain English

A high-severity security flaw in Apache Shiro from Apache Software Foundation. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.7% (higher than 52% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 4.0)8.2High
Exploit odds (30 days)0.7%top 47.9% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

When using Apache Shiro with the shiro-guice module in a web servlet context, a specially crafted HTTP request may cause an authentication bypass. This vulnerability is similar to https://www.cve.org/CVERecord?id=CVE-2020-1957 https://www.cve.org/CVERecord , except that it affects the `shiro-guice` module instead of the `shiro-spring` module. This issue affects all Apache Shiro versions through 2.x, and 3.0.0-alpha-1 only when using `shiro-guice` module in a web servlet context. Upgrade to version 3.0.0 or later, which fixes the issue.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12shirono fix listedDEBIAN-CVE-2026-56091
Debian:13shirono fix listedDEBIAN-CVE-2026-56091
Debian:14shirono fix listedDEBIAN-CVE-2026-56091
Mavenorg.apache.shiro:shiro-guice3.0.0GHSA-qj64-jj84-w38j
Ubuntu:22.04:LTSshirono fix listedUBUNTU-CVE-2026-56091
Ubuntu:25.10shirono fix listedUBUNTU-CVE-2026-56091
Ubuntu:26.04:LTSshirono fix listedUBUNTU-CVE-2026-56091
Ubuntu:26.10shirono fix listedUBUNTU-CVE-2026-56091

Affected products (as reported)

VendorProductVersions
Apache Software Foundation Apache Shiro 0 – through 2.99.993.0.0-alpha-0 – through 3.0.0-alpha-1

Weakness: CWE-289 · Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/S:P/AU:Y/V:D/RE:L/U:Amber

References