CVE-2026-53068 Overview
CVE-2026-53068 is an integer overflow vulnerability in the Linux kernel's drm/komeda driver. The flaw resides in the Arm Frame Buffer Compression (AFBC) framebuffer size validation logic. The driver calculates the minimum required buffer size by adding the AFBC payload size to the framebuffer offset without checking for arithmetic overflow.
When the addition overflows, the size check incorrectly succeeds. A local user can then supply an undersized drm_gem_object to the kernel, which may lead to out-of-bounds memory access during framebuffer processing. The Linux Verification Center identified the issue using the SVACE static analysis tool.
Critical Impact
Local attackers can trigger out-of-bounds memory access in the kernel by submitting crafted AFBC framebuffer parameters, potentially leading to memory corruption or denial of service.
Affected Products
- Linux kernel versions containing the drm/komeda driver prior to the fix commits
- Systems using Arm Mali Komeda display processors with AFBC support
- Distributions shipping vulnerable stable kernel branches referenced in the upstream fixes
Discovery Timeline
- 2026-06-24 - CVE-2026-53068 published to NVD
- 2026-06-24 - Last updated in NVD database
Technical Details for CVE-2026-53068
Vulnerability Analysis
The vulnerability exists in the AFBC framebuffer size validation routine within the Linux kernel's drm/komeda driver. The driver must verify that user-supplied framebuffer objects are large enough to hold compressed AFBC payload data before the display hardware accesses them.
The size validation computes offset + payload_size and compares the result against the size of the underlying Graphics Execution Manager (GEM) object. Because both operands are user-influenced and the addition is performed using unchecked arithmetic, a sufficiently large offset or payload_size causes the sum to wrap around to a small value. The wrapped value passes the size comparison even when the actual buffer is undersized.
With validation bypassed, the kernel proceeds to use the malformed framebuffer. Subsequent reads or writes against the drm_gem_object can access memory beyond the allocation boundary, producing out-of-bounds access conditions [CWE-190].
Root Cause
The root cause is missing overflow detection during arithmetic on attacker-controlled integer values. The driver trusted the result of an unchecked addition when validating buffer bounds. The upstream patches replace the direct addition with check_add_overflow(), which performs the calculation and signals overflow conditions so the driver can reject malformed framebuffers.
Attack Vector
Exploitation requires local access to the affected system and the ability to interact with the Direct Rendering Manager (DRM) interface. An unprivileged user with access to /dev/dri/* device nodes can submit a crafted DRM_IOCTL_MODE_ADDFB2 request specifying AFBC modifiers, a large offset, and a payload size chosen so their sum overflows. The driver accepts the framebuffer, and later operations trigger out-of-bounds access against the undersized GEM object.
Verified patches from the upstream kernel are referenced via the Kernel Git Commit 02ff8a7, Kernel Git Commit 779ec12, and additional stable branch commits listed in the references.
Detection Methods for CVE-2026-53068
Indicators of Compromise
- Unexpected kernel oops or panic messages referencing komeda or drm_gem functions in dmesg output
- Processes invoking DRM_IOCTL_MODE_ADDFB2 with AFBC modifiers and unusually large offsets[] or pitch values
- Crashes or memory errors detected by KASAN with stack frames pointing into the Komeda AFBC validation path
Detection Strategies
- Audit kernel versions across the fleet and compare against the upstream stable commits that introduce check_add_overflow() in the Komeda AFBC validation
- Enable Kernel Address Sanitizer (KASAN) on test systems to surface out-of-bounds reads triggered by malformed framebuffer submissions
- Monitor auditd for unexpected access to /dev/dri/card* and /dev/dri/renderD* device nodes by non-graphics processes
Monitoring Recommendations
- Forward kernel ring buffer logs to a central SIEM and alert on komeda driver faults or DRM-related oops events
- Track loaded kernel modules and driver versions through endpoint telemetry to identify hosts still running unpatched Komeda code
- Establish baselines for legitimate DRM ioctl usage on affected hardware and flag deviations involving AFBC modifiers
How to Mitigate CVE-2026-53068
Immediate Actions Required
- Apply the upstream stable kernel updates that introduce check_add_overflow() in the Komeda AFBC size validation routine
- Inventory systems using Arm Mali Komeda display hardware and prioritize patching of those hosts
- Restrict access to DRM device nodes so only trusted local users and graphics services can submit framebuffer ioctls
Patch Information
The vulnerability is resolved by the upstream Linux kernel commits referenced in the NVD record, including Kernel Git Commit 02ff8a7, Kernel Git Commit 779ec12, Kernel Git Commit 8165e8b, Kernel Git Commit 872d923, Kernel Git Commit a3a2a9b, Kernel Git Commit d8a5419, Kernel Git Commit e27b580, and Kernel Git Commit fe1f80f. Distribution vendors will integrate these commits into their respective stable kernel updates.
Workarounds
- Unload the komeda driver on systems that do not require Arm Mali display output until kernel updates are applied
- Tighten permissions on /dev/dri/* device nodes and remove unprivileged users from the video and render groups where feasible
- Disable AFBC framebuffer modifiers in user-space compositors on affected platforms until patched kernels are deployed
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
