CVE-2025-39902

A flaw was found in the Linux kernel’s SLUB memory allocator (mm/slub). The function object_err() — used for debugging object metadata (freelist pointer, redzone, etc.) — can access invalid pointers when reporting corruption, leading to a crash. In some cases, due to freelist corruption (e.g., detected by alloc_consistency_checks()), the pointer passed to object_err() is invalid; instead of accessing metadata.

This vulnerability is classified as Moderate impact because an attacker requires local access and must induce an invalid object state or pre-existing freelist corruption to trigger a kernel crash during error reporting. Under typical Red Hat Enterprise Linux workloads, these diagnostic code paths are executed only after slab consistency checks detect an anomaly. The blast radius is therefore confined to a local denial of service rather than arbitrary code execution or unauthenticated compromise.

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 don't meet the Red Hat Product Security criteria, comprising ease of use and deployment, applicability to widespread installation base or stability.