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CVE PROGRAM SOURCE RECORD9.8 Critical

CVE-2025-38527

smb: client: fix use-after-free in cifs_oplock_break

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Status
Published
Published
Updated
Assigning organization
Linux

Description

In the Linux kernel, the following vulnerability has been resolved: smb: client: fix use-after-free in cifs_oplock_break A race condition can occur in cifs_oplock_break() leading to a use-after-free of the cinode structure when unmounting: cifs_oplock_break() _cifsFileInfo_put(cfile) cifsFileInfo_put_final() cifs_sb_deactive() [last ref, start releasing sb] kill_sb() kill_anon_super() generic_shutdown_super() evict_inodes() dispose_list() evict() destroy_inode() call_rcu(&inode->i_rcu, i_callback) spin_lock(&cinode->open_file_lock) <- OK [later] i_callback() cifs_free_inode() kmem_cache_free(cinode) spin_unlock(&cinode->open_file_lock) <- UAF cifs_done_oplock_break(cinode) <- UAF The issue occurs when umount has already released its reference to the superblock. When _cifsFileInfo_put() calls cifs_sb_deactive(), this releases the last reference, triggering the immediate cleanup of all inodes under RCU. However, cifs_oplock_break() continues to access the cinode after this point, resulting in use-after-free. Fix this by holding an extra reference to the superblock during the entire oplock break operation. This ensures that the superblock and its inodes remain valid until the oplock break completes.

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

  • b98749cac4a695f084a5ff076f4510b23e353ecd to < 4256a483fe58af66a46cbf3dc48ff26e580d3308affected
  • b98749cac4a695f084a5ff076f4510b23e353ecd to < 0a4eec84d4d2c4085d4ed8630fd74e4b39033c1baffected
  • b98749cac4a695f084a5ff076f4510b23e353ecd to < 2baaf5bbab2ac474c4f92c10fcb3310f824db995affected
  • b98749cac4a695f084a5ff076f4510b23e353ecd to < 09bce2138a30ef10d8821c8c3f73a4ab7a5726bcaffected
  • b98749cac4a695f084a5ff076f4510b23e353ecd to < da11bd4b697b393a207f19a2ed7d382a811a3ddcaffected
  • b98749cac4a695f084a5ff076f4510b23e353ecd to < 705c79101ccf9edea5a00d761491a03ced314210affected
  • 2429fcf06d3cb962693868ab0a927c9038f12a2daffected
  • 1ee4f2d7cdcd4508cc3cbe3b2622d7177b89da12affected
  • 53fc31a4853e30d6e8f142b824f724da27ff3e40affected
  • 8092ecc306d81186a64cda42411121f4d35aaff4affected
  • ebac4d0adf68f8962bd82fcf483936edd6ec095baffected
  • 3.16.72 to < 3.17affected
  • 4.9.171 to < 4.10affected
  • 4.14.114 to < 4.15affected
  • 4.19.37 to < 4.20affected
  • 5.0.10 to < 5.1affected

Linux Linux

Default version status: affected

  • 5.1affected
  • 0 to < 5.1unaffected
  • 5.15.190 to ≤ 5.15.*unaffected
  • 6.1.147 to ≤ 6.1.*unaffected
  • 6.6.100 to ≤ 6.6.*unaffected
  • 6.12.40 to ≤ 6.12.*unaffected
  • 6.15.8 to ≤ 6.15.*unaffected
  • 6.16 to ≤ *unaffected

References