CVE-2025-21941 in Linux
Summary
by MITRE • 04/01/2025
In the Linux kernel, the following vulnerability has been resolved:
drm/amd/display: Fix null check for pipe_ctx->plane_state in resource_build_scaling_params
Null pointer dereference issue could occur when pipe_ctx->plane_state is null. The fix adds a check to ensure 'pipe_ctx->plane_state' is not null before accessing. This prevents a null pointer dereference.
Found by code review.
(cherry picked from commit 63e6a77ccf239337baa9b1e7787cde9fa0462092)
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 02/01/2026
The vulnerability identified as CVE-2025-21941 represents a critical null pointer dereference flaw within the Linux kernel's AMD display subsystem, specifically within the display resource management component. This issue resides in the drm/amd/display driver where the resource_build_scaling_params function fails to properly validate pointer references before attempting access operations. The vulnerability arises from insufficient input validation mechanisms that should have been implemented to prevent unauthorized memory access patterns. The flaw manifests when the pipe_ctx->plane_state pointer is null, yet the code attempts to dereference this pointer without proper null checking, creating a potential crash scenario that could be exploited by malicious actors.
The technical implementation of this vulnerability stems from a fundamental lack of defensive programming practices within the AMD display driver codebase. When the display subsystem processes graphics pipeline contexts, it assumes that pipe_ctx->plane_state will always contain a valid reference to a plane state structure. However, under certain conditions related to display configuration changes or resource allocation failures, this pointer can legitimately become null. The absence of proper null pointer validation creates a path where a null pointer dereference occurs, potentially leading to kernel crashes, system instability, or more severe exploitation scenarios. This type of vulnerability directly maps to CWE-476 which specifically addresses null pointer dereference conditions in software implementations.
The operational impact of this vulnerability extends beyond simple system crashes, potentially affecting the stability and reliability of systems running Linux kernels with AMD graphics hardware. When exploited, the null pointer dereference can cause the kernel to panic and reboot the entire system, leading to denial of service conditions that may be particularly problematic in server environments or embedded systems. The vulnerability's exploitation potential increases when considering that display drivers often run with elevated privileges and have direct access to hardware resources, making this a significant concern for system security. Additionally, this flaw could be leveraged as part of a broader attack chain where an attacker might use the system instability to execute further malicious payloads or escalate privileges.
Mitigation strategies for CVE-2025-21941 should focus on immediate codebase updates and comprehensive security hardening practices. The fix implemented in the Linux kernel demonstrates proper defensive programming by adding a null check before pointer access, which aligns with established security practices and represents a standard remediation approach for similar vulnerabilities. Organizations should prioritize applying the patched kernel version that includes the cherry-picked commit 63e6a77ccf239337baa9b1e7787cde9fa0462092. System administrators should also implement monitoring solutions to detect unusual system behavior that might indicate exploitation attempts, while maintaining regular kernel updates to prevent similar vulnerabilities from accumulating. The fix addresses the root cause by ensuring proper validation of pointer references before access, which adheres to the principle of least privilege and defensive programming principles recommended by various security frameworks including the ATT&CK framework's defense evasion techniques.