Cyber Resilience

CVE-2026-56091

Published
25 June 2026
Modified
25 June 2026
CVSS Score v4 8.2
Click a component to see what it means
Raw vectorCVSS: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
EPSS Score 0.0067 50th percentile
Risk Priority 44 floored blend · peak EPSS

CVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.

Summary

CVE-2026-56091 is a high-severity Authentication Bypass by Alternate Name (CWE-289) vulnerability in Apache Shiro (inferred from references). Its CVSS base score is 8.2 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked in the top 50% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to IA-2 (Identification and Authentication (Organizational Users)) and IA-4 (Identifier Management) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

A07:2025 Authentication Failures

EU & UK References

Vulnerability Data

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…

more

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.

CWE(s)
CWE-289

Related Threats

MITRE ATT&CK Enterprise Techniques

T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-3184Shared CWE-289
CVE-2023-38487Shared CWE-289
CVE-2024-56511Shared CWE-289
CVE-2026-24058Shared CWE-289
CVE-2026-23903Shared CWE-289
CVE-2023-51663Shared CWE-289
CVE-2025-64521Shared CWE-289
CVE-2025-8415Shared CWE-289
CVE-2026-8457Shared CWE-289
CVE-2026-9701Shared CWE-289

Affected Assets

Apache
Shiro
inferred from references and description; NVD did not file a CPE for this CVE

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)
  • 8 hardening rules · 3 OS baselines
Validate
Prove the fix (OWASP ASVS)
  • V8.3.3
  • V10.3.2
  • V6.4.3

Mitigating Controls (NIST 800-53 r5) AI

IA-2 Identification and Authentication (Organizational Users) good match

Requiring unique identification and authentication of users forces the system to resolve all name variants to a single identity before access is granted.

IA-4 Identifier Management good match

Identifier management directly requires authorization and uniqueness checks that eliminate alternate-name aliases for the same actor or resource.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.AA-01 partial match
prevents

Proper identity management reduces alternate-name collisions but does not guarantee canonicalization inside the auth decision.

PR.AA-03 partial match
prevents

Strong authentication mechanisms directly prevent name-based bypass when they enforce canonical name checks.

PR.AA-05 partial match
prevents

Authorization policy enforcement assumes correct identity; the weakness occurs before policy is applied.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.5.15 Access control partial match
prevents

Access-control policy can mandate canonical-name checks but does not prescribe the technical implementation.

A.5.16 Identity management partial match
prevents

Identity-management processes can require unique, canonical identifiers, reducing alternate-name bypass risk.

A.5.17 Authentication information partial match
degrades

Proper management of authentication credentials can include rules against duplicate or alias identities.

A.5.18 Access rights partial match
prevents

Access-rights provisioning can enforce canonical-name validation when granting rights.

A.8.3 Information access restriction partial match
prevents

Information-access-restriction mechanisms can implement canonical-name checks to prevent bypass.

A.8.5 Secure authentication partial match
prevents

Secure-authentication controls can require canonical identifiers and reject alternate names.

Hardening callouts derived

Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (higher-evidence rows only; rows rated `none` are excluded).

Oracle Linux 8 (1 rule)
  • V-248538 OL 8 operating systems booted with United Extensible Firmware Interface (UEFI) must have a unique name for the grub superusers account when booting into single-user mode and maintenance. prevents CWE-289
RHEL 7 (1 rule)
  • V-244558 Red Hat Enterprise Linux operating systems version 7.2 or newer booted with United Extensible Firmware Interface (UEFI) must have a unique name for the grub superusers account when booting into single-user mode and maintenance. prevents CWE-289

References