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
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| — | Linux Kernel before 4.13.6 | Linux Kernel before 4.13.6 | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | linux | 4.13.10-1 | — |
| Debian 13 | linux | 4.13.10-1 | — |
| Debian 12 | linux | 4.13.10-1 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 16.04 LTS | linux-azure | 4.13.0-1005.7 | — |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 7 | kernel-rt +10 | 3.10.0-862.rt56.804.el7 | RHSA-2018:0676 |
| RHEL 7 | perf +18 | 3.10.0-862.el7 | RHSA-2018:1062 |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 7 | perf +11 | 3.10.0-862.el7 | ELSA-2018-1062 |
Advisories 3
- RHSA-2018:1062 Red Hat Security Advisory: kernel security, bug fix, and enhancement update Red Hat Security Advisories (RHSA) · Jun 29, 2026
- RHSA-2018:0676 Red Hat Security Advisory: kernel-rt security, bug fix, and enhancement update Red Hat Security Advisories (RHSA) · Jun 29, 2026
- ELSA-2018-1062 Important: kernel security, bug fix, and enhancement update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Apr 16, 2018
References
- 102516 vdb-entry
- http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=384632e67e0829deb8015ee6ad916b180049d252
- https://bugzilla.redhat.com/show_bug.cgi?id=1523481
- RHSA-2018:1062 vendor-advisory
- https://github.com/torvalds/linux/commit/384632e67e0829deb8015ee6ad916b180049d252
- RHSA-2018:0676 vendor-advisory
- https://www.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.13.6
- https://access.redhat.com/security/cve/CVE-2017-15126