CVE-2026-98985: Linux kernel · namespace: check the mounts before reading their parents in pivot_root()
Source GCVE Database
Not known to be exploited · fixed in e3aba6900483f64e6c9eb328150dd633b7d36c1c : update Linux kernel when convenient.
Data as of 26 Oct 2026, 17:16 UTC
Rated by Threat Radar · CVSS not yet scored by NVD
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 6% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in e3aba6900483f64e6c9eb328150dd633b7d36c1c, a56d4f8f8f4c5d9ac339d5c03a9d90eecd3697fc, 6b7c001eb5857fa09041f47673666060a2e5fc1c +3
Exploitation evidence
Disclosed: evidence found.
CVE published 23 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| Fixed in– |
Description
In the Linux kernel, the following vulnerability has been resolved: namespace: check the mounts before reading their parents in pivot_root() path_pivot_root() reads the parents of new_root and of the caller's root and checks whether they are shared before it checks that either mount is in the caller's mount namespace. Only namespace_sem is held. That's fine for a mount that is in the caller's mount namespace. But new_root can be a file descriptor to a mount that has been unmounted and that only the file descriptor keeps alive. If that mount stayed attached to its parent when it was unmounted nothing pins the parent for it. The final mntput() of the parent unhooks the children under mount_lock alone and frees the parent afterwards: pivot_root() close(fd), last ref on the parent ------------ --------------------------------- ex_parent = new_mnt->mnt_parent mntput_no_expire_slowpath() __umount_mnt(new_mnt) cleanup_mnt() call_rcu() IS_MNT_SHARED(ex_parent) BUG: KASAN: slab-use-after-free in path_pivot_root+0xf1a/0x1840 Read of size 4 at addr ffff8881047382f8 by task pivot_widen/157 path_pivot_root+0xf1a/0x1840 __x64_sys_pivot_root+0x165/0x190 The same goes for the caller's root via chroot(). Both outcomes of the check end in EINVAL so nothing but the read itself goes wrong. It's the same thing commit bb4609405752 ("statmount: read the parent of an unmounted mount under mount_lock") fixed for statmount(). Check that both mounts are in the caller's namespace before their parents are read. Every path returns EINVAL either way.
References
- nvd.nist.gov/vuln/detail/CVE-2026-98985 (opens in a new tab)
- git.kernel.org/stable/c/3c2441e21c3df867e4131e0ff784ecdb3a7a55f8 (opens in a new tab)
- git.kernel.org/stable/c/3dad2330c89343ba083cf7868779083fd5fbe0fe (opens in a new tab)
- git.kernel.org/stable/c/6b7c001eb5857fa09041f47673666060a2e5fc1c (opens in a new tab)
- git.kernel.org/stable/c/a56d4f8f8f4c5d9ac339d5c03a9d90eecd3697fc (opens in a new tab)
- git.kernel.org/stable/c/e3aba6900483f64e6c9eb328150dd633b7d36c1c (opens in a new tab)