Review reviewHigh

CVE-2026-56091

Apache Software Foundation Apache Shiro

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.

CVSS: 8.2
EPSS: 0.42%
CISA KEV: Not listed
Published: 2026.06.25

PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV

Exploit probability0.42%

Technical severityCVSS 8.2

Vulnerability overview

Affected product and versions

Product: Apache Software Foundation Apache Shiro
Affected versions: 3.0.0-alpha-0
Fixed versions: No verified fixed-version field is available yet

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide

1
Identify
Confirm that Apache Software Foundation Apache Shiro and an affected version are present.
2
Prioritize
Combine exploitation signals with asset exposure and business criticality.
3
Remediate
Follow the vendor advisory or supported update path and preserve rollback options.
4
Verify
Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:P/AU:Y/R:X/V:D/RE:L/U:Amber
CWE: CWE-289