CVE-2025-39951

um: virtio_uml: Fix use-after-free after put_device in probe

CVE-2025-39951 is fixed in linux on 1 platform, first by DEBIAN-CVE-2025-39951, released October 4, 2025. It is not reported as exploited. Patch Radar priority: High.

High

CVSS

7.8

Moderate

Exploitation

None reported

No vendor assessment

CISA KEV

Not listed

Not in the Known Exploited Vulnerabilities catalog

EPSS

0.0015

4th percentile

In the Linux kernel, the following vulnerability has been resolved: um: virtio_uml: Fix use-after-free after put_device in probe When register_virtio_device() fails in virtio_uml_probe(), the code sets vu_dev->registered = 1 even though the device was not successfully registered. This can lead to use-after-free or other issues.

Where it's fixed

Product	Fixed in	Fix	Released
Linux
linux · Debian 12.15 (bookworm)	6.1.158-1	DEBIAN-CVE-2025-39951	Oct 4, 2025
linux · Debian 13.5 (trixie)	6.12.57-1	DEBIAN-CVE-2025-39951	Oct 4, 2025
linux · Debian 14	6.16.9-1	DEBIAN-CVE-2025-39951	Oct 4, 2025

Details

Published
October 4, 2025
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Vendor advisory
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-39951

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