CVE-2020-25220

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2020-09-10 · updated 2026-06-17
Weakness: CWE-416

Description

The Linux kernel 4.9.x before 4.9.233, 4.14.x before 4.14.194, and 4.19.x before 4.19.140 has a use-after-free because skcd->no_refcnt was not considered during a backport of a CVE-2020-14356 patch. This is related to the cgroups feature.

Affected products

Linux kernel: from 4.9.0 before 4.9.233; from 4.14 before 4.14.194; from 4.19 before 4.19.140 — fixed in 4.14.194, 4.19.140, 4.9.233

How to fix

Upgrade to a fixed version: Linux kernel 4.14.194, 4.19.140, 4.9.233. Check the vendor advisory for mitigations.

References

https://bugzilla.redhat.com/show_bug.cgi?id=1868453
https://cdn.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.14.194
https://cdn.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.19.140
https://cdn.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.9.233
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=linux-4.14.y&id=82fd2138a5ffd7e0d4320cdb669e115ee976a26e
https://lists.debian.org/debian-lts-announce/2020/10/msg00032.html
https://lists.debian.org/debian-lts-announce/2020/10/msg00034.html
https://security.netapp.com/advisory/ntap-20201001-0004/
https://www.spinics.net/lists/stable/msg405099.html
https://bugzilla.redhat.com/show_bug.cgi?id=1868453
https://cdn.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.14.194
https://cdn.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.19.140

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