CVE-2026-56091

Status: DeferredHigh (8.2)—

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

Version: 4.0
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
Base score: 8.2

Exploitation probability (EPSS)

Probability of exploitation in the next 30 days: 0.67%
Percentile among all scored CVEs: 50
Score date: 10/3/2026

EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).

🎯 ATT&CK techniques

How this vulnerability is exploited and what the attacker gains, in MITRE ATT&CK terms.

ExploitationT1190 Exploit Public-Facing Applicationinitial access85 %
Primary impactT1078.001 Default Accountsstealth · persistence · privilege escalation · initial access90 %
Secondary impactT1078 Valid Accountsstealth · persistence · privilege escalation · initial access85 %

Vulnerabilidad de bypass de autenticación en aplicación web expuesta (AV:N). Vector CVSS 4.0 con VC:H confirma impacto en confidencialidad. Permite obtención/reutilización de credenciales legítimas (T1078) mediante evasión de controles de autenticación.

Inferred by our analysis agent from the official description, CVSS vector and CWE, and checked by a supervisor. May contain errors.

🛡️ ATT&CK mitigations that cover these techniques

Privileged Account Management Password Policies Multi-factor Authentication Application Developer Guidance Active Directory Configuration Vulnerability Scanning

Affected technologies (2)

⚠ AI-inferred from the description — NVD hasn't analyzed this CVE yet, these aren't verified CPEs.

Apache — Shiro^AI Apache — Shiro-guice^AI

CWEs

CWE-289

References

https://lists.apache.org/thread/onmtxmy2qonbpx7xlw3o34x8sctv47r7

Raw JSON (NVD)

Show

{
  "id": "CVE-2026-56091",
  "cveTags": [],
  "metrics": {
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          "id": "CVE-2026-56091",
          "role": "CISA Coordinator",
          "options": [
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            },
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          "version": "2.0.3",
          "timestamp": "2026-06-25T12:10:08.791843Z"
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          "integrityRequirement": "NOT_DEFINED",
          "modifiedAttackVector": "NOT_DEFINED",
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          "vulnerabilityResponseEffort": "LOW",
          "modifiedSubAvailabilityImpact": "NOT_DEFINED",
          "modifiedVulnAvailabilityImpact": "NOT_DEFINED",
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          "versions": [
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  "published": "2026-06-25T09:16:46.103",
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      "value": "When using Apache Shiro with the shiro-guice module in a web servlet context, a specially crafted HTTP request may cause an authentication bypass.\nThis 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.\n\nThis 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.\n\nUpgrade to version 3.0.0 or later, which fixes the issue."
    }
  ],
  "lastModified": "2026-06-25T13:27:40.747",
  "sourceIdentifier": "security@apache.org"
}