Bug 2461487 (CVE-2026-31583)

Summary: CVE-2026-31583 kernel: media: em28xx: fix use-after-free in em28xx_v4l2_open()
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's em28xx media driver. This vulnerability, a type of memory corruption, arises from a race condition where the driver attempts to use memory that has already been freed or access a null pointer. This can be triggered when the `em28xx_v4l2_open()` function is called without proper synchronization. Successful exploitation could lead to system instability or a denial of service, making the system unresponsive.
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Description OSIDB Bzimport 2026-04-24 15:04:24 UTC 
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 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.
Comment 1 Keith Grant 2026-04-24 18:34:17 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026042412-CVE-2026-31583-edcc@gregkh/T