CVE-2026-97557

CVE CVE-2026-97557EUVD EUVD-2026-86865Published 2026-09-25T10:21:47.000ZLast changed 2026-09-25T14:41:13.000ZCVSS 7.5

What the advisory describes

In the Linux kernel, the following vulnerability has been resolved: smb: client: avoid leaking refcount in cifs_queue_oplock_break() cifs_queue_oplock_break() unconditionally takes a reference on the target file before queueing cifs_oplock_break(). Only that work item decreases the reference counter again. If another oplock break arrives while that work is still queued, queue_work() will return false and not queue this second work item. As a result, we will never reach the point to drop the file reference again and are leaking this reference. This can be triggered when interacting with a slow-responding server. As a result, later unmount operations for this file system will fail with BUG: Dentry ... still in use (1) [unmount of cifs cifs] VFS: Busy inodes after unmount of cifs (cifs) kernel BUG at fs/super.c:777! Fix this by only incrementing the reference count if the work has been queued successfully. Taking it after queue_work() is safe because all three callers hold tcon->open_file_lock across the call and _cifsFileInfo_put() decrements under that same lock, so a worker that starts the handler in the window cannot drop the reference before it has been taken.

Source: EUVD (ENISA), in the words of the advisory.

Products the advisory names

These come from the advisory itself, not from any check we performed.

Linux — Linux 5.1; patch: 0; b98749cac4a695f084a5ff076f4510b23e353ecd <af0193bbf1ac8c0f67f972998b0cc629d6116cf6; patch: 6.12.111; 3.16.72 <3.17; b98749cac4a695f084a5ff076f4510b23e353ecd <dfe7b750c7e069873a8a57a11c816831a235618a; b98749cac4a695f084a5ff076f4510b23e353ecd <9f2e63f1b2d5fc5b5423424902c091123e220e7e; 4.14.114 <4.15; 5.0.10 <5.1; patch: 7.2.7; b98749cac4a695f084a5ff076f4510b23e353ecd <2ed2c29dd9593637cfa25ac1eb23241b20202778; ebac4d0adf68f8962bd82fcf483936edd6ec095b; 4.19.37 <4.20; 4.9.171 <4.10; 1ee4f2d7cdcd4508cc3cbe3b2622d7177b89da12; patch: 6.18.53; patch: 7.3-rc3; 8092ecc306d81186a64cda42411121f4d35aaff4; 2429fcf06d3cb962693868ab0a927c9038f12a2d; 53fc31a4853e30d6e8f142b824f724da27ff3e40

The versions shown are the advisory's own. Patchlage compares no version numbers and derives no judgement from them — which version is installed is something a person has to look up.

Carried in the product catalogue

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Linux — Linux

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