What's the vulnerability?
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.
Business impact & how R4IM helps
This advisory is on our active-exploitation watchlist. Attackers are using it for initial access, privilege escalation or lateral movement in real-world intrusions. R4IM's offensive security and SOC teams already have detections, exploit replicas and remediation playbooks for this issue.
Targeted vulnerability assessment to confirm which of your assets are actually exploitable — not just theoretically affected.
Our pentesters chain this CVE into realistic attack paths so you see business impact, not just a scan finding.
If the affected product is internet-facing, our AppSec team will harden it against this and related OWASP-class issues.
Continuous monitoring with custom detections for this CVE deployed across your endpoints, identity and cloud.
Recommended remediation
- Inventory all assets running the affected vendor and product, including shadow IT and third-party hosted instances.
- Apply the vendor patch or mitigation referenced in the advisories below. Where no patch exists, isolate the asset or restrict network exposure.
- Hunt for indicators of prior compromise — exploitation of this class of bug often predates public disclosure.
- Deploy detections for the exploit primitives (network signature, EDR rule, WAF rule) and re-test after remediation.
Need help executing these steps? Our team typically completes validation and remediation within a single patch cycle. Request remediation support →
Vendor & research references
- https://access.redhat.com/errata/RHSA-2026:71609 · secalert@redhat.com
- https://access.redhat.com/errata/RHSA-2026:75571 · secalert@redhat.com
- https://access.redhat.com/errata/RHSA-2026:75579 · secalert@redhat.com
- https://access.redhat.com/errata/RHSA-2026:75580 · secalert@redhat.com
- https://access.redhat.com/errata/RHSA-2026:82939 · secalert@redhat.com
- https://access.redhat.com/errata/RHSA-2026:86633 · secalert@redhat.com
- https://access.redhat.com/errata/RHSA-2026:86634 · secalert@redhat.com
- https://access.redhat.com/errata/RHSA-2026:86635 · secalert@redhat.com
- https://access.redhat.com/errata/RHSA-2026:87026 · secalert@redhat.com
- https://access.redhat.com/security/cve/CVE-2026-96512 · secalert@redhat.com
- https://bugzilla.redhat.com/show_bug.cgi?id=2539327 · secalert@redhat.com
- https://github.com/sudo-project/sudo/commit/1820a349687522f51023d1ae5925125f59679a8c · secalert@redhat.com
- http://www.openwall.com/lists/oss-security/2026/09/24/4 · af854a3a-2127-422b-91ae-364da2661108
