CVE-2018-20856

Severity: high (CVSS 7.8 v3.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.7% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2019-07-26 · updated 2026-06-17
Weakness: CWE-416

Description

An issue was discovered in the Linux kernel before 4.18.7. In block/blk-core.c, there is an __blk_drain_queue() use-after-free because a certain error case is mishandled.

Affected products

Linux kernel: before 4.18.7 — fixed in 4.18.7

How to fix

Upgrade to a fixed version: Linux kernel 4.18.7. Check the vendor advisory for mitigations.

References

http://packetstormsecurity.com/files/154059/Slackware-Security-Advisory-Slackware-14.2-kernel-Updates.html
http://packetstormsecurity.com/files/154408/Kernel-Live-Patch-Security-Notice-LSN-0055-1.html
http://packetstormsecurity.com/files/154951/Kernel-Live-Patch-Security-Notice-LSN-0058-1.html
https://access.redhat.com/errata/RHSA-2019:3055
https://access.redhat.com/errata/RHSA-2019:3076
https://access.redhat.com/errata/RHSA-2019:3089
https://access.redhat.com/errata/RHSA-2019:3217
https://access.redhat.com/errata/RHSA-2020:0100
https://access.redhat.com/errata/RHSA-2020:0103
https://access.redhat.com/errata/RHSA-2020:0543
https://access.redhat.com/errata/RHSA-2020:0664
https://access.redhat.com/errata/RHSA-2020:0698

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