CVE-2017-15126

Severity: high (CVSS 8.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 4.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2018-01-14 · updated 2026-06-17
Weakness: CWE-119

Description

A use-after-free flaw was found in fs/userfaultfd.c in the Linux kernel before 4.13.6. The issue is related to the handling of fork failure when dealing with event messages. Failure to fork correctly can lead to a situation where a fork event will be removed from an already freed list of events with userfaultfd_ctx_put().

Affected products

Linux kernel: from 4.11 before 4.13.6 — fixed in 4.13.6

How to fix

Upgrade to a fixed version: Linux kernel 4.13.6. Check the vendor advisory for mitigations.

References

http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=384632e67e0829deb8015ee6ad916b180049d252
http://www.securityfocus.com/bid/102516
https://access.redhat.com/errata/RHSA-2018:0676
https://access.redhat.com/errata/RHSA-2018:1062
https://access.redhat.com/security/cve/CVE-2017-15126
https://bugzilla.redhat.com/show_bug.cgi?id=1523481
https://github.com/torvalds/linux/commit/384632e67e0829deb8015ee6ad916b180049d252
https://www.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.13.6
http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=384632e67e0829deb8015ee6ad916b180049d252
http://www.securityfocus.com/bid/102516
https://access.redhat.com/errata/RHSA-2018:0676
https://access.redhat.com/errata/RHSA-2018:1062

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