CVE-2026-72034fhandle: reject detached mounts in capable_wrt_mount()
Updated under an hour ago ()
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No exploitation reported and no EPSS estimate yet.
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In the Linux kernel, the following vulnerability has been resolved: fhandle: reject detached mounts in capable_wrt_mount() The recent fhandle RCU fix moved the mount namespace capability check into capable_wrt_mount(), so a non-NULL mnt_namespace survives the ns_capable() dereference. The helper still assumes the later READ_ONCE(mount->mnt_ns) must be non-NULL because may_decode_fh() checked is_mounted() first. That assumption is not stable. A detached mount from open_tree(..., OPEN_TREE_CLONE) can be dissolved on fput while open_by_handle_at() is between those checks, and umount_tree() can clear mount->mnt_ns. If the helper observes NULL, it dereferences mnt_ns->user_ns and panics. Return false when the RCU read observes a detached mount. This keeps the relaxed permission path conservative: a mount no longer attached to a namespace cannot authorize open_by_handle_at() access.
- CVSS
- 7.8 HIGH (v3.1, CNA)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Weakness (CWE)
- Not given
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Linux
- NVD analysis
- Received
- Record last updated
- Oct 16, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Linux Linux linux:linux (from the name) | from 620c266f394932e5decc4b34683a75dfc59dc2f4 before 15104234c267ebe04b9f9a73e5c2179cc265ff60; 620c266f394932e5decc4b34683a75dfc59dc2f4 builds before 6c52226072a3c61337b1eec1799bb987748884fa; 620c266f394932e5decc4b34683a75dfc59dc2f4 builds before 6ee183d89261bf1d1cf9f06d80a40dab8f36ee55; 620c266f394932e5decc4b34683a75dfc59dc2f4 builds before 6c732471740bc2ac9b0946134f9f551dc75f4369 | CNA record |
References
- https://git.kernel.org/stable/c/15104234c267ebe04b9f9a73e5c2179cc265ff60
- https://git.kernel.org/stable/c/6c52226072a3c61337b1eec1799bb987748884fa
- https://git.kernel.org/stable/c/6ee183d89261bf1d1cf9f06d80a40dab8f36ee55
- https://git.kernel.org/stable/c/6c732471740bc2ac9b0946134f9f551dc75f4369
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.