CVE-2026-80927

A flaw was found in the Linux kernel. A race condition in the timekeeping subsystem, specifically within the __do_adjtimex() function, can occur when the auxiliary clock is handled. This allows uninitialized stack data to be used in calculations and subsequently leaked to userspace, leading to information disclosure.

A flaw rated MODERATE by Red Hat was found in the Linux kernel timekeeping subsystem. When handling an adjtimex() request, a race condition in __do_adjtimex() can occur if the auxiliary clock is disabled during a call to tk_get_aux_ts64() but is re-enabled before tks->clock_valid is checked. If this narrow timing window is hit, uninitialized stack data is used in the adjustment calculations and can be indirectly leaked to userspace, resulting in an information disclosure. Exploitation requires a local, low-privileged attacker able to issue adjtimex() calls on a system that uses an auxiliary clock and to win the race window. This issue affects the kernel in Red Hat Enterprise Linux 10, where the fix is currently deferred to a future update; the residual risk until the fix lands is limited to a local leak of uninitialized kernel stack data. Red Hat Enterprise Linux 6, 7, 8, and 9, and Red Hat OpenShift (RHEL CoreOS) are not affected because the vulnerable code, introduced upstream in Linux 6.17, is not present in the kernel versions shipped for those products. Upstream also notes that a similar race window exists for the core timekeeper, but in that case the only effect is incorrect time adjustments, which userspace is responsible for avoiding.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.