Answer in brief
CVE-2025-38527 records a Unknown severity vulnerability in smb: client: fix use-after-free in cifs_oplock_break. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
Answer in brief
CVE-2025-38527 records a Unknown severity vulnerability in smb: client: fix use-after-free in cifs_oplock_break. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=b98749cac4a695f084a5ff076f4510b23e353ecd <4256a483fe58af66a46cbf3dc48ff26e580d3308 || >=b98749cac4a695f084a5ff076f4510b23e353ecd <0a4eec84d4d2c4085d4ed8630fd74e4b39033c1b || >=b98749cac4a695f084a5ff076f4510b23e353ecd <2baaf5bbab2ac474c4f92c10fcb3310f824db995 || >=b98749cac4a695f084a5ff076f4510b23e353ecd <09bce2138a30ef10d8821c8c3f73a4ab7a5726bc || >=b98749cac4a695f084a5ff076f4510b23e353ecd <da11bd4b697b393a207f19a2ed7d382a811a3ddc || >=b98749cac4a695f084a5ff076f4510b23e353ecd <705c79101ccf9edea5a00d761491a03ced314210 || 2429fcf06d3cb962693868ab0a927c9038f12a2d || 1ee4f2d7cdcd4508cc3cbe3b2622d7177b89da12 || 53fc31a4853e30d6e8f142b824f724da27ff3e40 || 8092ecc306d81186a64cda42411121f4d35aaff4 || ebac4d0adf68f8962bd82fcf483936edd6ec095b || >=3.16.72 <3.17 || >=4.9.171 <4.10 || >=4.14.114 <4.15 || >=4.19.37 <4.20 || >=5.0.10 <5.1 | 4256a483fe58af66a46cbf3dc48ff26e580d3308, 0a4eec84d4d2c4085d4ed8630fd74e4b39033c1b, 2baaf5bbab2ac474c4f92c10fcb3310f824db995, 09bce2138a30ef10d8821c8c3f73a4ab7a5726bc, da11bd4b697b393a207f19a2ed7d382a811a3ddc, 705c79101ccf9edea5a00d761491a03ced314210, 3.17, 4.10, 4.15, 4.20, 5.1 |
| Linux/Linuxgeneric | 5.1 | Not reported |
Published upstream
Aug 16, 2025
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Aug 5, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 5, 2026
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.
Quoted source text, attributed separately from HOL analysis.
A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=b98749cac4a695f084a5ff076f4510b23e353ecd <4256a483fe58af66a46cbf3dc48ff26e580d3308 || >=b98749cac4a695f084a5ff076f4510b23e353ecd <0a4eec84d4d2c4085d4ed8630fd74e4b39033c1b || >=b98749cac4a695f084a5ff076f4510b23e353ecd <2baaf5bbab2ac474c4f92c10fcb3310f824db995 || >=b98749cac4a695f084a5ff076f4510b23e353ecd <09bce2138a30ef10d8821c8c3f73a4ab7a5726bc || >=b98749cac4a695f084a5ff076f4510b23e353ecd <da11bd4b697b393a207f19a2ed7d382a811a3ddc || >=b98749cac4a695f084a5ff076f4510b23e353ecd <705c79101ccf9edea5a00d761491a03ced314210 || 2429fcf06d3cb962693868ab0a927c9038f12a2d || 1ee4f2d7cdcd4508cc3cbe3b2622d7177b89da12 || 53fc31a4853e30d6e8f142b824f724da27ff3e40 || 8092ecc306d81186a64cda42411121f4d35aaff4 || ebac4d0adf68f8962bd82fcf483936edd6ec095b || >=3.16.72 <3.17 || >=4.9.171 <4.10 || >=4.14.114 <4.15 || >=4.19.37 <4.20 || >=5.0.10 <5.1 | 4256a483fe58af66a46cbf3dc48ff26e580d3308, 0a4eec84d4d2c4085d4ed8630fd74e4b39033c1b, 2baaf5bbab2ac474c4f92c10fcb3310f824db995, 09bce2138a30ef10d8821c8c3f73a4ab7a5726bc, da11bd4b697b393a207f19a2ed7d382a811a3ddc, 705c79101ccf9edea5a00d761491a03ced314210, 3.17, 4.10, 4.15, 4.20, 5.1 |
| Linux/Linuxgeneric | 5.1 | Not reported |
Published upstream
Aug 16, 2025
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Aug 5, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 5, 2026
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.
Quoted source text, attributed separately from HOL analysis.