CVE-2026-80927
Description
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.
Statement
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.
Mitigation
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.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5.5 | N/A | N/A |
| Attack Vector | Local | N/A | N/A |
| Attack Complexity | Low | N/A | N/A |
| Privileges Required | Low | N/A | N/A |
| User Interaction | None | N/A | N/A |
| Scope | Unchanged | N/A | N/A |
| Confidentiality | None | N/A | N/A |
| Integrity Impact | None | N/A | N/A |
| Availability Impact | High | N/A | N/A |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Understanding the Weakness (CWE)
Integrity,Other
Technical Impact: Alter Execution Logic; Unexpected State
The attacker can gain access to otherwise unauthorized resources.
Integrity,Other
Technical Impact: Modify Application Data; Modify Files or Directories; Modify Memory; Other
Race conditions such as this kind may be employed to gain read or write access to resources which are not normally readable or writable by the user in question.
Integrity,Other
Technical Impact: Other
The resource in question, or other resources (through the corrupted one), may be changed in undesirable ways by a malicious user.
Non-Repudiation
Technical Impact: Hide Activities
If a file or other resource is written in this method, as opposed to in a valid way, logging of the activity may not occur.
Non-Repudiation,Other
Technical Impact: Other
In some cases it may be possible to delete files a malicious user might not otherwise have access to, such as log files.
Other
Technical Impact: Unexpected State
The product may perform invalid actions when the resource is in an unexpected state.
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