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TI-2026-79783 Aliases CVE-2026-98990GHSA-5v88-6pxr-8v5g

Busy mounts can be unmounted in Linux kernel namespace code

Priority LOW 22Published · Updated

Key facts

Attack vector
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Privileges required
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User interaction
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Attack complexity
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Impact type
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Confidentiality · integrity · availability
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Fix status
Partial Red Hat: 7 without a fix

No CVSS vector from any source. Fix status from CNA and Red Hat.

Summary

Several Linux kernel version ranges are affected, starting at 4.1.40. When a synchronous umount unmounts several mounts, the busy check runs before earlier unmounts change the mount tree, so a mount still in use elsewhere can be unmounted. A caller of a synchronous umount on a shrinkable mount, such as an automounted NFS, AFS or CIFS submount, can trigger this.

Written with Claude Haiku 5.5 from the sources below · 2026-11-06

Description from the CNA

In the Linux kernel, the following vulnerability has been resolved: namespace: check a submount for references right before unmounting it shrink_submounts() and mark_mounts_for_expiry() first collect all the mounts they are allowed to unmount and then unmount them. Whether a mount is busy is decided by propagate_mount_busy() on the tree. But unmounting the first mount changes the tree that the second one propagates into. propagate_umount() moves a surviving overmount off a copy it unmounts and mounts it where the copy was mounted. If that's where the propagated copy of the second victim is looked up the overmount becomes a candidate of the second umount_tree(). It's childless and so trim_one() commits it without looking at its reference count. So a synchronous umount pulls out a busy mount that is in use somewhere else and marks it MNT_SYNC_UMOUNT while it has users: umount2(/tmp/plshrink/p1, 0) = 0 errno 0 cwd is (unreachable) The same two umounts requested one after the other fail with EBUSY. This needs a mount with MNT_SHRINKABLE, i.e., automounted submounts of NFS, AFS and CIFS or the tracefs mount below debugfs. Bind mounts inherit the flag. Check each mount right before it is unmounted under the same hold of namespace_sem and mount_lock as the umount itself. Make sure that the algorithm stays linear.

Why it matters now

EPSS 0.00185 8th percentileScored 2026-11-07
Fix Partial Linux (Linux): 4.2, 4.5, 4.10 +9Red Hat: 7 without a fix

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

VendorProductAffected versionsFixed inStatusSource
LinuxLinux4.1.40 to before 4.2; 4.4.54 to before 4.5; 4.9.15 to before 4.10; 4.10.3 to before 4.114.2, 4.5, 4.10, 4.11Patch availableCNA
LinuxLinux4.11 and later5.10.273, 5.15.224, 6.1.191, 6.6.160, 6.12.113, 6.18.57, 7.2.11, 7.3Patch availableCNA
  • Linux VendorLinux Affected 4.1.40 to before 4.2; 4.4.54 to before 4.5; 4.9.15 to before 4.10; 4.10.3 to before 4.11 Fixed in 4.2, 4.5, 4.10, 4.11 Patch available CNA
  • Linux VendorLinux Affected 4.11 and later Fixed in 5.10.273, 5.15.224, 6.1.191, 6.6.160, 6.12.113, 6.18.57, 7.2.11, 7.3 Patch available CNA

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*——Linux
  • cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions — — ·Linux

Remediation

Fixed Linux kernel versions are 4.2, 4.5, 4.10, 4.11, 5.10.273, 5.15.224, 6.1.191, 6.6.160, 6.12.113, 6.18.57, 7.2.11 and 7.3. Red Hat lists the plan as no fix planned for Red Hat Enterprise Linux 6 and none available for Red Hat Enterprise Linux 7, 8, 9 and 10 and for Red Hat OpenShift Container Platform 4 and 5.

Written with Claude Haiku 5.5 from the sources below · 2026-11-06

  • Fix · CNA Linux (Linux) Fixed in 4.2, 4.5, 4.10, 4.11
  • Fix · CNA Linux (Linux) Fixed in 5.10.273, 5.15.224, 6.1.191, 6.6.160, 6.12.113, 6.18.57, 7.2.11, 7.3

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Enterprise Linux 10AffectedNo fix yet: Fix deferred
Red Hat Enterprise Linux 6AffectedNo fix planned: Out of support scope
Red Hat Enterprise Linux 7AffectedNo fix yet: Fix deferred
Red Hat Enterprise Linux 8AffectedNo fix yet: Fix deferred
Red Hat Enterprise Linux 9AffectedNo fix yet: Fix deferred
Red Hat OpenShift Container Platform 4AffectedNo fix yet: Fix deferred
Red Hat OpenShift Container Platform 5AffectedNo fix yet: Fix deferred

Timeline

  1. 2026-10-23 Threatist record created from CVE-2026-98990
  2. 2026-10-23 Alias added: GHSA-5v88-6pxr-8v5g
  3. 2026-10-30 Affected versions changed · Red Hat
  4. 2026-10-30 CVSS score added · Red Hat
  5. 2026-10-30 Fix available: Linux/Linux@361f59e7f3f9a219fb5567bf9abc8482a154a399, Linux/Linux@3f55f71291e4332983cd63b288d1f2be3c9c08fc, Linux/[email protected] +3 · CNA
  6. 2026-10-30 3 new references · CNA
  7. 2026-11-06 Affected versions changed · Red Hat

References

Other 8

  • TI-2025-26358 tls: fix handling of zero-length records on the rx_list KEVCVSS 3.1CRITICAL 9.8
  • TI-2026-38352 netfilter: bridge: make ebt_snat ARP rewrite writable KEVCVSS 3.1HIGH 8.8
  • TI-2021-02452 Incorrect authorization in Ubuntu linux kernel KEVCVSS 3.1HIGH 8.8
  • TI-2013-05264 The (1) get_user and (2) put_user API functions in the Linux kernel before 3.5.5 on the… KEVCVSS 3.1HIGH 8.8
  • TI-2022-00125 Integer overflow in kernel KEVCVSS 3.1HIGH 8.4
  • TI-2013-01864 The perf_swevent_init function in kernel/events/core.c in the Linux kernel before 3.8.9… KEVCVSS 3.1HIGH 8.4
See all 21741 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences