Improper access control in OpenBao - CVE-2026-40264

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Main Vulnerability Database Vulnerabilities #VU126698

Improper access control in OpenBao - CVE-2026-40264

Published: April 21, 2026


Vulnerability identifier: #VU126698
CSH Severity: Low
CVSS v4: 4.6 [CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:A/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-40264
CWE-ID: CWE-284
Exploitation vector: Remote access
Exploit availability: No public exploit available

Vulnerability details

The vulnerability allows a remote user to cause a denial of service.

The vulnerability exists due to improper access control in the token store when handling token renewal or revocation across namespaces. A remote privileged user can renew or revoke a token from another namespace to cause a denial of service.

Exploitation requires a leaked token accessor and affects cross-namespace tenant isolation.


Affected software

OpenBao
Fedora
openbao

How to mitigate CVE-2026-40264

Install security update from vendor's website.

OpenBao - update to 2.5.3
openbao - addressed in versions 2.5.3-1.el8, 2.5.3-1.el9, 2.5.3-1.el10_1, 2.5.3-1.el10_2, 2.5.3-1.el10_3, 2.5.3-1.fc42, 2.5.3-1.fc43, 2.5.3-1.fc44

External References

Related Security Bulletins