CVE-2017-5551

Severity: medium (CVSS 4.4 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: 2017-02-06 · updated 2026-06-17

Description

The simple_set_acl function in fs/posix_acl.c in the Linux kernel before 4.9.6 preserves the setgid bit during a setxattr call involving a tmpfs filesystem, which allows local users to gain group privileges by leveraging the existence of a setgid program with restrictions on execute permissions. NOTE: this vulnerability exists because of an incomplete fix for CVE-2016-7097.

Affected products

Linux kernel: through 4.9.5

References

http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=497de07d89c1410d76a15bec2bb41f24a2a89f31
http://www.debian.org/security/2017/dsa-3791
http://www.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.9.6
http://www.openwall.com/lists/oss-security/2017/01/21/3
http://www.securityfocus.com/bid/95717
http://www.securitytracker.com/id/1038053
https://bugzilla.redhat.com/show_bug.cgi?id=1416126
https://github.com/torvalds/linux/commit/497de07d89c1410d76a15bec2bb41f24a2a89f31
http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=497de07d89c1410d76a15bec2bb41f24a2a89f31
http://www.debian.org/security/2017/dsa-3791
http://www.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.9.6
http://www.openwall.com/lists/oss-security/2017/01/21/3

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