CVE-2026-68108 in Linux
Summary
by MITRE • 08/10/2026
In the Linux kernel, the following vulnerability has been resolved:
drm/amdgpu/vce: fix integer overflow in image size
Fix a security vulnerability where malicious VCE command streams with oversized dimensions (e.g. 65536×65536) cause 32-bit integer overflow, wrapping the calculated buffer size to 0. This bypasses validation and allows GPU firmware to perform out-of-bound memory access.
The fix uses 64-bit arithmetic to detect overflow and rejects invalid dimensions before they reach the hardware.
V2: remove redundant check V3: modify max height value V4: remove size64
(cherry picked from commit cbe408dba581755ad1279a487ec786d8927d778d)
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Analysis
by VulDB Data Team • 08/10/2026
The vulnerability in question affects the amdgpu driver within the Linux kernel, specifically impacting the Video Coding Engine component responsible for handling video encoding operations. This issue stems from inadequate input validation when processing VCE command streams that contain oversized image dimensions exceeding normal operational parameters. The flaw manifests as a 32-bit integer overflow occurring during buffer size calculations when processing image dimensions of 65536×65536 pixels or larger, creating a critical security risk that bypasses existing validation mechanisms.
The technical implementation of this vulnerability exploits the fundamental weakness in arithmetic operations within the GPU firmware processing pipeline. When malicious command streams specify excessively large dimensions, the calculation of required buffer space undergoes integer overflow, causing the resulting 32-bit value to wrap around to zero. This zero-sized buffer calculation bypasses all validation checks that should normally prevent dangerous memory operations, allowing the GPU firmware to attempt out-of-bounds memory access patterns that could potentially lead to privilege escalation or system instability. The vulnerability aligns with CWE-190, which specifically addresses integer overflow conditions, and represents a classic example of how arithmetic overflows can be exploited for bypassing security controls.
The operational impact of this vulnerability extends beyond simple denial of service scenarios, as it creates potential pathways for unauthorized access to GPU memory spaces and could enable attackers to manipulate firmware behavior through carefully crafted command sequences. The fix implemented addresses this by upgrading the arithmetic operations from 32-bit to 64-bit calculations, which provides sufficient range to detect overflow conditions before they can be processed by the hardware. This approach follows established security practices for preventing integer overflows as outlined in various exploit prevention methodologies and aligns with defensive programming principles that emphasize robust input validation and arithmetic safety.
The mitigation strategy employed in this fix demonstrates a mature understanding of security engineering principles, utilizing 64-bit arithmetic to detect potential overflow conditions rather than relying on traditional bounds checking approaches. This method provides superior protection against similar vulnerabilities by ensuring that invalid dimensions are rejected at the earliest possible stage of processing, before any hardware-level operations can be initiated with potentially malicious parameters. The iterative development process reflected in the version history shows careful consideration of redundant checks and optimization of maximum value constraints, ultimately resulting in a more robust solution that maintains performance while eliminating the security risk. This vulnerability resolution exemplifies the importance of proper integer handling in kernel space code and demonstrates how seemingly minor arithmetic operations can create significant security implications when not properly validated against overflow conditions.