CVE-2026-31583
Published: 24 April 2026
Summary
CVE-2026-31583 is a high-severity Use After Free (CWE-416) vulnerability in Linux Linux Kernel. Its CVSS base score is 7.8 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 2.6th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified are NIST 800-53 SI-16 (Memory Protection) and SI-2 (Flaw Remediation).
Deeper analysis
CVE-2026-31583 is a use-after-free vulnerability in the Linux kernel's media subsystem, specifically within the em28xx V4L2 driver. The issue arises in the em28xx_v4l2_open() function, which reads dev->v4l2 without acquiring dev->lock. This creates a race condition with em28xx_v4l2_init()'s error path and em28xx_v4l2_fini(), both of which free the em28xx_v4l2 struct and set dev->v4l2 to NULL while holding the lock. As a result, attackers can trigger a use-after-free when v4l2_fh_init() accesses the embedded video_device's ctrl_handler, or a NULL pointer dereference in em28xx_resolution_set() when accessing v4l2->norm after dev->v4l2 is nulled. The vulnerability is rated 7.8 on the CVSS 3.1 scale (AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H) and maps to CWE-416 (Use After Free).
A local attacker with low privileges can exploit this vulnerability by racing the open operation against concurrent initialization or finalization paths in the em28xx driver. Successful exploitation could lead to arbitrary code execution, information disclosure, or denial of service through memory corruption via the use-after-free, or system crashes from the NULL dereference, given the high impact on confidentiality, integrity, and availability.
Mitigation involves applying the upstream kernel patches referenced in the stable git commits, such as 5fb2940327722b4684d2f964b54c1c90aa277324, 6b9e66437cc6123ddedac141e1b8b6fcf57d2972, 871b8ea8ef39a6c253594649f4339378fad3d0dd, a66485a934c7187ae8e36517d40615fa2e961cff, and b5d141ea15f173f15b9f0a72965902f3428c0d92. These patches fix the race by moving the mutex_lock() before the dev->v4l2 read and adding a NULL check under the lock. Security practitioners should update affected Linux kernels, particularly those using em28xx hardware like USB video capture devices, and monitor for backported fixes in downstream distributions.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-25476
Vulnerability details
In the Linux kernel, the following vulnerability has been resolved: media: em28xx: fix use-after-free in em28xx_v4l2_open() em28xx_v4l2_open() reads dev->v4l2 without holding dev->lock, creating a race with em28xx_v4l2_init()'s error path and em28xx_v4l2_fini(), both of which free the em28xx_v4l2 struct and set…
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dev->v4l2 to NULL under dev->lock. This race leads to two issues: - use-after-free in v4l2_fh_init() when accessing vdev->ctrl_handler, since the video_device is embedded in the freed em28xx_v4l2 struct. - NULL pointer dereference in em28xx_resolution_set() when accessing v4l2->norm, since dev->v4l2 has been set to NULL. Fix this by moving the mutex_lock() before the dev->v4l2 read and adding a NULL check for dev->v4l2 under the lock.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Local use-after-free in kernel driver (em28xx V4L2) directly enables privilege escalation via memory corruption and arbitrary code execution from low-privileged context.
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Directly mitigates the use-after-free vulnerability by requiring timely remediation through application of the specific Linux kernel patches that fix the race condition in the em28xx driver.
Protects kernel memory from unauthorized code execution that could result from exploitation of the use-after-free in the em28xx_v4l2 struct.
Prevents exploitation by disabling or restricting the unnecessary em28xx V4L2 driver functionality in systems not requiring USB video capture devices.