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CVE PROGRAM SOURCE RECORDUnscored

CVE-2026-98984

dcache: don't put a mountpoint on a dentry that's being removed

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Status
Published
Published
Updated
Assigning organization
Linux

Description

In the Linux kernel, the following vulnerability has been resolved: dcache: don't put a mountpoint on a dentry that's being removed rmdir(), unlink() and rename() call dont_mount() on the victim and then detach_mounts() with the victim's inode locked. do_lock_mount() takes the inode lock of the mountpoint and checks cant_mount() so a mount can't show up after detach_mounts(). But attach_recursive_mnt() makes a second mountpoint for the root of the source mount so that the mounts already located at the destination can be put on top of it. No inode is locked for that one and d_set_mounted() only refuses a dentry that is unlinked. Between detach_mounts() and d_delete() the victim is still hashed: rmrace: b passed dont_mount() and detach_mounts(), sleeping T2: move_mount(S, /tmp/plcant/x, BENEATH) = 0 errno 0 () T1: rmdir(/tmp/plcant/d/b) = 0 errno 0 109 107 0:61 /d/b//deleted /tmp/plcant/x rw,relatime - tmpfs tmpfs rw 108 109 0:63 / /tmp/plcant/x rw,relatime - tmpfs T rw A bind mount of the directory that's being removed is moved beneath an existing mount while the rmdir() is located between the two calls. The mount ends up on the removed directory and nothing will ever detach it. Check cant_mount() in d_set_mounted() as well. dont_mount() raises the flag under d_lock before detach_mounts() runs so either the mountpoint is set first and detach_mounts() finds the mount or the flag is seen and the mount is refused.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

Linux Linux

Default version status: unaffected

  • 1064f874abc0d05eeed8993815f584d847b72486 to < 25e3ce3e2ebdd8ed3fc19dc1f7e3bc487f9240f3affected
  • 1064f874abc0d05eeed8993815f584d847b72486 to < 982d231ad863bb14f7bda4852ab942c0203cec4baffected
  • 1064f874abc0d05eeed8993815f584d847b72486 to < 96ca40461d8b91e13061ec4afb59bae6f07a516aaffected
  • 1064f874abc0d05eeed8993815f584d847b72486 to < 5e6bfd9f249f2c74bb63c0f06ad959da3bee0971affected
  • 1064f874abc0d05eeed8993815f584d847b72486 to < 793cb67b0f52d00c67bd0e76bc57455b5c70ebb8affected
  • 1064f874abc0d05eeed8993815f584d847b72486 to < 390ddcea2a8aca411b931a8e2863a80ccca8d2b3affected
  • 1064f874abc0d05eeed8993815f584d847b72486 to < 30a1625022411a387cce9239408ece9955bc9c58affected
  • 1064f874abc0d05eeed8993815f584d847b72486 to < 75f4197f1e11d2eb75c2d6f916a7d4764db621e5affected
  • 5e6ef5ef6eaf690faad3a7c6c665ebf45d7b6ccfaffected
  • 839d42687dfce0ed0ea2c6bd8d707cc0e276fbe7affected
  • 808e83e5add13152bd4a88346487de68395c136baffected
  • 6de9d08a9718ee9c12ba6343c50141c2d633e3dcaffected
  • 4.1.40 to < 4.2affected
  • 4.4.54 to < 4.5affected
  • 4.9.15 to < 4.10affected
  • 4.10.3 to < 4.11affected

Linux Linux

Default version status: affected

  • 4.11affected
  • 0 to < 4.11unaffected
  • 5.10.273 to ≤ 5.10.*unaffected
  • 5.15.224 to ≤ 5.15.*unaffected
  • 6.1.191 to ≤ 6.1.*unaffected
  • 6.6.160 to ≤ 6.6.*unaffected
  • 6.12.113 to ≤ 6.12.*unaffected
  • 6.18.57 to ≤ 6.18.*unaffected
  • 7.2.11 to ≤ 7.2.*unaffected
  • 7.3 to ≤ *unaffected

References