CVE-2026-96512: Sudo: sudo: tz environment variable allows bypass of notbefore/notafter time-based authorization

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-09-23 · updated 2026-10-29
Weakness: CWE-863

Description

A flaw was found in sudo. When sudoers rules use NOTBEFORE or NOTAFTER time-based access restrictions with timestamps that omit the trailing 'Z' timezone indicator, the time evaluation relies on the TZ environment variable inherited from the calling user. Because sudo is a setuid-root program, an unprivileged local user can set TZ to an extreme timezone offset to shift the authorization window by up to approximately 25 hours, causing expired rules to be treated as valid. This allows the user to execute commands outside the intended time window. Authentication is not bypassed; only the time-based authorization check is affected.

Affected products

Red Hat Enterprise Linux 10: all versions — fixed in 0:1.9.17-10.p2.el10_2.7
Red Hat Enterprise Linux 10.0 Extended Update Support: all versions — fixed in 0:1.9.15-8.p5.el10_0.5
Red Hat Enterprise Linux 7 Extended Lifecycle Support: all versions — fixed in 0:1.8.23-10.el7_9.6
Red Hat Enterprise Linux 8: all versions — fixed in 0:1.9.5p2-2.el8_10
Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support: all versions — fixed in 0:1.8.29-7.el8_4.4
Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On: all versions — fixed in 0:1.8.29-7.el8_4.4
Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support: all versions — fixed in 0:1.9.5p2-1.el8_6.4
Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On: all versions — fixed in 0:1.9.5p2-1.el8_6.4
Red Hat Enterprise Linux 8.8 Telecommunications Update Service: all versions — fixed in 0:1.9.5p2-1.el8_8.4
Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions: all versions — fixed in 0:1.9.5p2-1.el8_8.4
Red Hat Enterprise Linux 9: all versions — fixed in 0:1.9.17p2-3.el9_8.3
Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions: all versions — fixed in 0:1.9.5p2-9.el9_2.5
Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions: all versions — fixed in 0:1.9.5p2-10.el9_4.4
Red Hat Enterprise Linux 9.6 Extended Update Support: all versions — fixed in 0:1.9.5p2-10.el9_6.4
Red Hat Hardened Images: all versions — fixed in 1.9.17-16.p2.2.hum1
Red Hat OpenShift AI 3.0: all versions — fixed in 1793041981
Red Hat OpenShift AI 3.4: all versions — fixed in 1793042006
Red Hat Update Infrastructure 5: all versions — fixed in 1791964013

How to fix

Upgrade to a fixed version: Red Hat Enterprise Linux 10 0:1.9.17-10.p2.el10_2.7; Red Hat Enterprise Linux 10.0 Extended Update Support 0:1.9.15-8.p5.el10_0.5; Red Hat Enterprise Linux 7 Extended Lifecycle Support 0:1.8.23-10.el7_9.6; Red Hat Enterprise Linux 8 0:1.9.5p2-2.el8_10; Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support 0:1.8.29-7.el8_4.4; Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On 0:1.8.29-7.el8_4.4; Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support 0:1.9.5p2-1.el8_6.4; Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On 0:1.9.5p2-1.el8_6.4; Red Hat Enterprise Linux 8.8 Telecommunications Update Service 0:1.9.5p2-1.el8_8.4; Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions 0:1.9.5p2-1.el8_8.4; Red Hat Enterprise Linux 9 0:1.9.17p2-3.el9_8.3; Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions 0:1.9.5p2-9.el9_2.5. Check the vendor advisory for mitigations.

References

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