CVE-2017-5551
kernel: S_ISGD is not cleared when setting posix ACLs in tmpfs (CVE-2016-7097 incomplete fix)
Severity
ModerateRed Hat Product Security
CVSS 3.0
Review impact separately from score.
Published · January 9, 2017
Updated · June 28, 2026
Description
A vulnerability was found in the Linux kernel in 'tmpfs' file system. When file permissions are modified via 'chmod' and the user is not in the owning group or capable of CAP_FSETID, the setgid bit is cleared in inode_change_ok(). Setting a POSIX ACL via 'setxattr' sets the file permissions as well as the new ACL, but doesn't clear the setgid bit in a similar way; this allows to bypass the check in 'chmod'.
Statement
This issue affects the Linux kernel packages as shipped with Red Hat Enterprise Linux 5. This has been rated as having Moderate security impact and is not currently planned to be addressed in future updates. For additional information, refer to the Red Hat Enterprise Linux Life Cycle: https://access.redhat.com/support/policy/updates/errata/.
This issue affects the Linux kernel packages as shipped with Red Hat Enterprise Linux 6, 7 and MRG-2. Future Linux kernel updates for the respective releases might address this issue.
This flaw was fixed in the Red Hat products as a part of the CVE-2016-7097 fix.
CVSS score applicability
The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.
Mitigation
No mitigation is specified in collected source.
CVSS / CWE
CVSS 3.0 · 4.4CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N
CWE-287 · Improper Authentication