CVE-2026-52907: Linux Kernel Rockchip RKCIF Off-by-One Memory Access Vulnerability

Technical summary

CVE-2026-52907 is a CWE-193 off-by-one error in the media/rockchip/rkcif subsystem of the Linux kernel. Array boundary checks use > comparisons when >= is required, allowing access to memory one element beyond valid array bounds. The vulnerability permits both read and write operations to out-of-bounds memory. The fix replaces vulnerable comparisons and replaces hard-coded _MAX enum values with ARRAY_SIZE macros for better maintainability and correctness.

Business impact

Systems running vulnerable Linux kernel versions with Rockchip camera hardware face potential data exfiltration, privilege escalation, and denial of service. Organizations relying on embedded Linux devices with Rockchip SoCs—common in automotive, industrial IoT, and consumer electronics—should assess exposure. While exploitation requires local access, the combination of high confidentiality, integrity, and availability impact (C:H/I:H/A:H in the CVSS vector) makes this significant for kernel-hardening programs and supply chain security.

Affected systems

The Linux kernel is affected across all versions containing the vulnerable rkcif driver code. Impact is limited to systems with Rockchip-based hardware (common in ARM SoCs used in embedded and mobile devices). Desktop and server systems without Rockchip camera interface hardware are unaffected. Check your kernel source tree for drivers/media/platform/rockchip/rkciif.c to determine if the vulnerable code path exists in your build.

Exploitability

Exploitation requires local access (AV:L) with standard user privileges (PR:L). No special conditions are needed (AC:L). An attacker must be able to trigger the camera interface driver code path, which may occur through camera initialization, format negotiation, or buffer management operations. The vulnerability does not require user interaction. Practical exploitation would depend on exposing the driver through a user-accessible interface and crafting input to trigger the out-of-bounds access.

Remediation

Apply kernel updates containing the fix committed to the rkcif driver. Verify that your kernel version includes the boundary check correction and ARRAY_SIZE macro conversion. Distributions should backport the fix to stable and long-term support branches. Until patching is feasible, restrict access to camera devices via filesystem permissions and disable unnecessary camera functionality if not required.

Patch guidance

Obtain the latest kernel from your distribution or kernel.org. The fix resolves the comparison logic in array bounds checks within the rkcif driver. Verify the patch against the upstream Linux kernel repository to confirm the specific changeset. Test camera functionality after patching to ensure no regression. For embedded systems, coordinate with your SoC vendor (Rockchip) and device manufacturer to obtain kernel updates, as they may not follow upstream release cadence.

Detection guidance

Monitor kernel logs for out-of-bounds memory access warnings or panics related to the rkcif driver. Kernel Address Sanitizer (KASAN) and similar runtime instrumentation can detect off-by-one memory operations. Review sysfs and /proc entries related to camera devices for unusual access patterns. Intrusion detection systems may flag attempts to read/write invalid memory regions if the kernel enforces such boundaries. Static analysis tools scanning kernel source for array boundary issues can identify vulnerable code before deployment.

Why prioritize this

This vulnerability merits prompt attention due to its HIGH CVSS 7.8 score reflecting full confidentiality, integrity, and availability impact. While local access is required, the rkcif driver may be accessible to unprivileged processes on systems with public camera support. Rockchip SoCs are prevalent in IoT and automotive embedded Linux deployments where the attack surface may be larger than expected. Kernel vulnerabilities affecting core subsystems warrant prioritization in hardening roadmaps.

Risk score, explained

The CVSS 3.1 score of 7.8 (HIGH) reflects: local attack vector (AV:L, narrowing scope but not zero-day context); low complexity (AC:L, straightforward trigger); low privilege requirement (PR:L, not requiring admin); no user interaction (UI:N); high impact across confidentiality (C:H—kernel memory leaks), integrity (I:H—buffer corruption), and availability (A:H—potential DoS). The elevated score acknowledges that kernel-level access to memory can cascade into privilege escalation or system compromise, despite the local-only attack surface.

Frequently asked questions