Kernel compromise via CIFS oplock-break use-after-free
Published Aug 16, 2025 · Updated Aug 5, 2026
Use-after-free in the Linux CIFS client allows remote attackers controlling an SMB peer to compromise the kernel during unmount. cifs_oplock_break releases the last superblock reference through _cifsFileInfo_put, then accesses the freed cinode after RCU inode cleanup. Reachability requires an existing CIFS mount, and a malicious or on-path SMB server can stall the oplock-break worker until teardown triggers kernel disclosure, corruption, or panic.
Summary
What happened
Use-after-free in the Linux CIFS client allows remote attackers controlling an SMB peer to compromise the kernel during unmount. cifs_oplock_break releases the last superblock reference through _cifsFileInfo_put, then accesses the freed cinode after RCU inode cleanup. Reachability requires an existing CIFS mount, and a malicious or on-path SMB server can stall the oplock-break worker until teardown triggers kernel disclosure, corruption, or panic.
The record
- CVE
- CVE-2025-38527
- Published
- Aug 16, 2025
- Updated
- Aug 5, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- CWE-416, T1203
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Aug 16, 2025CVE publishedPublication date reported by the CVE source.
- Aug 5, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=1ee4f2d7cdcd4508cc3cbe3b2622d7177b89da12
- Affected versionversion=2429fcf06d3cb962693868ab0a927c9038f12a2d
- Affected versionversion=3.16.72 <3.17
- Affected versionversion=4.14.114 <4.15
- Affected versionversion=4.19.37 <4.20
- Affected versionversion=4.9.171 <4.10
- Affected versionversion=5.0.10 <5.1
- Affected versionversion=5.1
- Affected versionversion=53fc31a4853e30d6e8f142b824f724da27ff3e40
- Affected versionversion=8092ecc306d81186a64cda42411121f4d35aaff4
- Affected versionversion=b98749cac4a695f084a5ff076f4510b23e353ecd <09bce2138a30ef10d8821c8c3f73a4ab7a5726bc
- Affected versionversion=b98749cac4a695f084a5ff076f4510b23e353ecd <0a4eec84d4d2c4085d4ed8630fd74e4b39033c1b
- Affected versionversion=b98749cac4a695f084a5ff076f4510b23e353ecd <2baaf5bbab2ac474c4f92c10fcb3310f824db995
- Affected versionversion=b98749cac4a695f084a5ff076f4510b23e353ecd <4256a483fe58af66a46cbf3dc48ff26e580d3308
- Affected versionversion=b98749cac4a695f084a5ff076f4510b23e353ecd <705c79101ccf9edea5a00d761491a03ced314210
- Affected versionversion=b98749cac4a695f084a5ff076f4510b23e353ecd <da11bd4b697b393a207f19a2ed7d382a811a3ddc
- Affected versionversion=ebac4d0adf68f8962bd82fcf483936edd6ec095b
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
What attackers are doing with it
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Public exploit references
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Technologies
Your stack
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Your stack
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