CVE-2026-98977namespace: handle mount locking for automounts correctly
- —Not scoredno CVSS score yet
- 0.22%Exploitation in 30 daysEPSS · top 87% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
In the Linux kernel, the following vulnerability has been resolved: namespace: handle mount locking for automounts correctly If mounts are propagated across user namespaces, attach_recursive_mnt() locks every copy of the source mount to protect overmounts from vanishing and revealing the underlying files or directories. The user namespace is taken from the caller's mount namespaces since this is where the mounts end up. Except, that's not always true. Automounts may legitimately get popped in by tasks located in a different mount and user namespace during path lookup. Then check doesn't make sense at that point. The copy in the namespace of the parent - which may be the host's - is now locked and the host cannot change the flags of its own mounts anymore. Here's the reproducer: - host has debugfs mounted nosuid,nodev,noexec and shared - tracefs automount below it is not yet active - hand a child process a directory descriptor on that mount - child process enters auser and mount namespace - child process' namespace now holds a locked copy of the host's debugfs mount that receives propagation from it - child process stats "tracing/." through the descriptor - lookup runs on the host's mount so the automount lands below the host's mount - propagation puts a copy below the child's copy - both try to clear the flags on the mount they got, with a bind remount: host, on its own automount: MS_REMOUNT|MS_BIND = EPERM child, on the copy in its namespace: MS_REMOUNT|MS_BIND = 0 So the lock landed on the host's mount instead of the child's copy. Congrats. So we need to compare with the owner of the namespace the mount actually gets mounted on. For all regular cases that is the caller's mount namespace and so nothing changes. Detached trees in anonymous mount namespaces by be handed over via SCM_RIGHTS or inherited in other ways on purpose so the attaching task's mount namespace is authoritative, not the creator of the detached tree.
Timeline
ID reserved
By Linux
- 28 days later
· 28 days later
Published
- 7 days later
· 7 days later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
No CVSS score yet: neither the CNA, CISA nor NVD has scored this CVE. NVD status: Received.
- EPSS (exploitation in 30 days)
- 0.22% · top 87% of all CVEs (15 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: Not scored.
Affected products
- affected 132c94e31b8bca8ea921f9f96a57d684fa4ae0a9 – < f9b488641cfa63f9b41321530c543688b2e34f03
- affected 132c94e31b8bca8ea921f9f96a57d684fa4ae0a9 – < 91676705756af6a59a515087b8b854c8a28d12eb
- affected 132c94e31b8bca8ea921f9f96a57d684fa4ae0a9 – < 587d25c4b13d49c8fd05df2f71240f73bb2a058c
- affected 132c94e31b8bca8ea921f9f96a57d684fa4ae0a9 – < 5e8f3ac8fa3d411b422ad32b9168c46a4824cc79
- affected 132c94e31b8bca8ea921f9f96a57d684fa4ae0a9 – < b3ccde78f1608836e62320428abc0e8aa9cf2329
- affected 132c94e31b8bca8ea921f9f96a57d684fa4ae0a9 – < e01c79761c7b3373e80094c5eadb21cb864fa8bc
- affected 132c94e31b8bca8ea921f9f96a57d684fa4ae0a9 – < 6ab37fae14196ba2262b152a7d9222c50356d278
- affected 132c94e31b8bca8ea921f9f96a57d684fa4ae0a9 – < 33aadc7c72055fca93cb5a3691d836ebf8b31c9b
- affected 9c773201d61272db49f8f33a83a3cb2a3fe4b14f
- affected 3.8.6 – < 3.9
- affected 3.9
- unaffected < 3.9
- unaffected 5.10.273 – ≤ 5.10.*
- unaffected 5.15.224 – ≤ 5.15.*
- unaffected 6.1.191 – ≤ 6.1.*
- unaffected 6.6.160 – ≤ 6.6.*
- unaffected 6.12.114 – ≤ 6.12.*
- unaffected 6.18.57 – ≤ 6.18.*
- unaffected 7.2.11 – ≤ 7.2.*
- unaffected 7.3 – ≤ *
References
References8
- https://git.kernel.org/stable/c/f9b488641cfa63f9b41321530c543688b2e34f03 (opens in a new tab)
- https://git.kernel.org/stable/c/91676705756af6a59a515087b8b854c8a28d12eb (opens in a new tab)
- https://git.kernel.org/stable/c/587d25c4b13d49c8fd05df2f71240f73bb2a058c (opens in a new tab)
- https://git.kernel.org/stable/c/5e8f3ac8fa3d411b422ad32b9168c46a4824cc79 (opens in a new tab)
- https://git.kernel.org/stable/c/b3ccde78f1608836e62320428abc0e8aa9cf2329 (opens in a new tab)
- https://git.kernel.org/stable/c/e01c79761c7b3373e80094c5eadb21cb864fa8bc (opens in a new tab)
- https://git.kernel.org/stable/c/6ab37fae14196ba2262b152a7d9222c50356d278 (opens in a new tab)
- https://git.kernel.org/stable/c/33aadc7c72055fca93cb5a3691d836ebf8b31c9b (opens in a new tab)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-108771 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2026-98977)Record last updated .