The do_umount function in fs/namespace.c in the Linux kernel through 3.17 does not require the CAP_SYS_ADMIN capability for do_remount_sb calls that change the root filesystem to read-only, which allows local users to cause a denial of service (loss of writability) by making certain unshare system calls, clearing the / MNT_LOCKED flag, and making an MNT_FORCE umount system call.
The MITRE CVE dictionary describes this issue as:
Find out more about CVE-2014-7975 from the MITRE CVE dictionary dictionary and NIST NVD.
This issue does not affect the versions of the kernel package as shipped with
Red Hat Enterprise Linux 5, 6, 7 and Red Hat Enterprise MRG 2.
| Base Score | 2.9 |
|---|---|
| Base Metrics | AV:A/AC:M/Au:N/C:N/I:N/A:P |
| Access Vector | Adjacent Network |
| Access Complexity | Medium |
| Authentication | None |
| Confidentiality Impact | None |
| Integrity Impact | None |
| Availability Impact | Partial |
Find out more about Red Hat support for the Common Vulnerability Scoring System (CVSS).
| Platform | Errata | Release Date |
|---|---|---|
| Red Hat Enterprise Linux 7 (kernel) | RHSA-2017:1842 | 2017-08-01 |
| Red Hat Enterprise Linux for Real Time for NFV (v. 7) (kernel-rt) | RHSA-2017:2077 | 2017-08-01 |
| Platform | Package | State |
|---|---|---|
| Red Hat Enterprise MRG 2 | realtime-krenel | Not affected |
| Red Hat Enterprise Linux 6 | kernel | Not affected |
| Red Hat Enterprise Linux 5 | kernel | Not affected |
Vulmon