CVE-2026-97576
Description
A flaw was found in the Linux kernel's Video4Linux2 (V4L2) subsystem. A local attacker can exploit this flaw by submitting a crafted High Efficiency Video Coding (HEVC) control structure with tile counts that exceed array limits. Because the kernel fails to validate these bounds properly, this issue can lead to an out-of-bounds memory read, resulting in a system crash and Denial of Service (DoS).
Statement
A moderate severity flaw was found in the Linux kernel's Video4Linux2 (V4L2) subsystem. The compound-control validation performed by std_validate_compound() did not bound the High Efficiency Video Coding (HEVC) picture parameter set (PPS) tile counts, num_tile_columns_minus1 and num_tile_rows_minus1, against the capacity of the column_width_minus1[] and row_height_minus1[] uAPI arrays. A local attacker with access to a V4L2 stateless HEVC decoding device could submit a crafted V4L2_CTRL_TYPE_HEVC_PPS control with tiling enabled and tile counts exceeding the array capacity; stateless HEVC decoder drivers would then read beyond those arrays and use the invalid values as tile-loop bounds, causing an out-of-bounds read that can crash the kernel and result in denial of service.
Red Hat Enterprise Linux 8 and earlier streams, including the RHEL 6, 7, and 8 kernels (and kernel-rt where shipped) and OpenShift Container Platform versions shipping RHEL 8 based CoreOS, are not affected because the vulnerable code is not present. Red Hat Enterprise Linux 9 and 10 (kernel and kernel-rt), Red Hat In-Vehicle OS, and OpenShift Container Platform versions built on RHEL 9 based CoreOS are affected, with fixes deferred to future planned updates given the moderate severity and local, availability-only impact of this issue. The residual risk is that a local user with access to a V4L2 stateless HEVC decode device node can trigger a kernel crash and denial of service.
Red Hat rates this flaw Moderate with a CVSS 3.1 base score of 5.5 (AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H). This differs from the upstream CVE.org severity of Important (7.8, C:H/I:H/A:H) because the out-of-bounds read values are consumed internally by the decoder drivers as loop bounds and are not disclosed to user space, limiting the impact to availability rather than confidentiality or integrity.
Mitigation
Exploitation requires local access to a V4L2 stateless HEVC decoding device node. As a workaround, restrict access to video device nodes (for example /dev/video*) to trusted users only, for instance by removing untrusted users from the video group or otherwise limiting permissions on the device nodes, so that unprivileged local users cannot submit the crafted HEVC PPS control structures that trigger this flaw.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5.5 | N/A | 7.8 |
| Attack Vector | Local | N/A | Local |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | Low | N/A | Low |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | None | N/A | High |
| Integrity Impact | None | N/A | High |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
cve.org: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Understanding the Weakness (CWE)
Confidentiality
Technical Impact: Read Memory
An attacker could get secret values such as cryptographic keys, PII, memory addresses, or other information that could be used in additional attacks.
Confidentiality
Technical Impact: Bypass Protection Mechanism
Out-of-bounds memory could contain memory addresses or other information that can be used to bypass ASLR and other protection mechanisms in order to improve the reliability of exploiting a separate weakness for code execution.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
An attacker could cause a segmentation fault or crash by causing memory to be read outside of the bounds of the buffer. This is especially likely when the code reads a variable amount of data and assumes that a sentinel exists to stop the read operation, such as a NUL in a string.
Other
Technical Impact: Varies by Context
The read operation could produce other undefined or unexpected results.
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