Linux Kernel EUVD-2026-59527

Exploitation requires all of the following: local user-level access to a Linux system (physical console, SSH, or container breakout); the system must be running on Tegra SoC hardware with the host1x GPU driver (CONFIG_TEGRA_HOST1X) compiled and loaded; and the attacker must have permission to access the host1x device node (typically /dev/host1x or similar), which usually requires membership in the 'video' or 'render' group, or explicit device ACL grants. The vulnerability is only reachable through the GPU job submission path in pin_job(); it is not triggered by normal system operation without a GPU workload. The CVSS PR:L confirms that low-privileged local authentication is required - remote unauthenticated exploitation is not possible. Systems without Tegra GPU hardware or with the host1x driver absent or not loaded are not affected, regardless of kernel version.

The CVSS 8.8 with AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H signals a credible local privilege escalation path: a low-privileged user with GPU device access triggers a silent mapping failure, the kernel proceeds with an invalid DMA buffer, and memory corruption follows. The Scope:Changed metric correctly reflects that a kernel driver bug can compromise the entire host. However, the real-world exploitation bar is meaningfully high: the bug requires Tegra-specific hardware (host1x GPU driver), the IOMMU failure condition must be reliably triggerable by an attacker, and no public exploit or CISA KEV listing exists. EPSS at 0.17% (7th percentile) corroborates this - even a mid-sized municipal IT team in radom managing a fleet of Tegra-based embedded Linux nodes should treat this as a routine patch-cycle item rather than an emergency response, given the targeted hardware dependency and the absence of weaponized exploit code. The sole signal tension is between the CVSS 8.8 severity and the very low EPSS: this is expected and not contradictory, as CVSS models worst-case theoretical impact while EPSS reflects observed exploitation activity. No conflicting vendor versus NVD signals detected.

An attacker with a local shell on a Tegra-based Linux system (such as an NVIDIA Jetson board or Tegra-based industrial device) submits a GPU job that causes iommu_map_sgtable() to return a negative error code. Because pin_job() stores the result in an int and uses incorrect comparison logic, the error is silently treated as success, and the GPU job proceeds with an unmapped or invalid DMA buffer. This triggers kernel memory corruption that a sophisticated attacker could chain into arbitrary kernel code execution and full privilege escalation to root. No public exploit code has been identified at time of analysis.