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Vulnerability record · CVE-2020-25656 · published 2 December 2020

CVE-2020-25656: Linux kernel use after free vulnerability

Linux · Linux Kernel

A flaw was found in the Linux kernel. A use-after-free was found in the way the console subsystem was using ioctls KDGKBSENT and KDSKBSENT. A local user could use this flaw to get read memory access out of bounds. The highest threat from this vulnerability is to data confidentiality.

4.1 CVSS 3.1 Medium EPSS 0.44% · top 64.3% CWE-416 · Use after free
4.1CVSS 3.1 base score, v2 1.9
0.44%EPSS exploitation probability, 30 days
NoNot in CISA KEV
4Affected product versions listed by NVD
12References, 4 tagged exploit
17 Jun 2026Last modified by NVD

Description

A flaw was found in the Linux kernel. A use-after-free was found in the way the console subsystem was using ioctls KDGKBSENT and KDSKBSENT. A local user could use this flaw to get read memory access out of bounds. The highest threat from this vulnerability is to data confidentiality.

CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:N/A:N

Affected products

4 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://bugzilla.redhat.com/show_bug.cgi?id=1888726 ExploitIssue TrackingPatchThird Party Advisory
https://lists.debian.org/debian-lts-announce/2020/12/msg00015.html Mailing ListThird Party Advisory
https://lists.debian.org/debian-lts-announce/2020/12/msg00027.html Mailing ListThird Party Advisory
https://lkml.org/lkml/2020/10/16/84 ExploitMailing ListThird Party Advisory
https://lkml.org/lkml/2020/10/29/528 Mailing ListPatchThird Party Advisory
https://www.starwindsoftware.com/security/sw-20210325-0006/ Third Party Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=1888726 ExploitIssue TrackingPatchThird Party Advisory
https://lists.debian.org/debian-lts-announce/2020/12/msg00015.html Mailing ListThird Party Advisory
https://lists.debian.org/debian-lts-announce/2020/12/msg00027.html Mailing ListThird Party Advisory
https://lkml.org/lkml/2020/10/16/84 ExploitMailing ListThird Party Advisory
https://lkml.org/lkml/2020/10/29/528 Mailing ListPatchThird Party Advisory
https://www.starwindsoftware.com/security/sw-20210325-0006/ Third Party Advisory

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Source: NIST National Vulnerability Database (record CVE-2020-25656), CISA KEV, FIRST EPSS (scores of 2026-09-29). This page is refreshed as NVD updates the record.