CVE-2015-4177

Severity: medium (CVSS 5.5 v3.0)
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: 2016-05-02 · updated 2026-06-17

Description

The collect_mounts function in fs/namespace.c in the Linux kernel before 4.0.5 does not properly consider that it may execute after a path has been unmounted, which allows local users to cause a denial of service (system crash) by leveraging user-namespace root access for an MNT_DETACH umount2 system call.

Affected products

Linux kernel: through 4.0.4

References

http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=cd4a40174b71acd021877341684d8bb1dc8ea4ae
http://openwall.com/lists/oss-security/2015/05/29/10
http://openwall.com/lists/oss-security/2015/05/29/5
http://www.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.0.5
http://www.openwall.com/lists/oss-security/2015/06/04/5
https://bugzilla.redhat.com/show_bug.cgi?id=1248486
https://github.com/torvalds/linux/commit/cd4a40174b71acd021877341684d8bb1dc8ea4ae
http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=cd4a40174b71acd021877341684d8bb1dc8ea4ae
http://openwall.com/lists/oss-security/2015/05/29/10
http://openwall.com/lists/oss-security/2015/05/29/5
http://www.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.0.5
http://www.openwall.com/lists/oss-security/2015/06/04/5

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