{"id":"CVE-2026-97557","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: avoid leaking refcount in cifs_queue_oplock_break()\n\ncifs_queue_oplock_break() unconditionally takes a reference on the\ntarget file before queueing cifs_op…","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: avoid leaking refcount in cifs_queue_oplock_break()\n\ncifs_queue_oplock_break() unconditionally takes a reference on the\ntarget file before queueing cifs_op…","severity":"high","cvss":7.5,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","vendor":"Linux","product":"Linux","affected":["Linux >= b98749cac4a695f084a5ff076f4510b23e353ecd < af0193bbf1ac8c0f67f972998b0cc629d6116cf6","Linux >= b98749cac4a695f084a5ff076f4510b23e353ecd < 2ed2c29dd9593637cfa25ac1eb23241b20202778","Linux >= b98749cac4a695f084a5ff076f4510b23e353ecd < dfe7b750c7e069873a8a57a11c816831a235618a","Linux >= b98749cac4a695f084a5ff076f4510b23e353ecd < 9f2e63f1b2d5fc5b5423424902c091123e220e7e","Linux 2429fcf06d3cb962693868ab0a927c9038f12a2d","Linux 1ee4f2d7cdcd4508cc3cbe3b2622d7177b89da12","Linux 53fc31a4853e30d6e8f142b824f724da27ff3e40","Linux 8092ecc306d81186a64cda42411121f4d35aaff4","Linux ebac4d0adf68f8962bd82fcf483936edd6ec095b","Linux >= 3.16.72 < 3.17","Linux >= 4.9.171 < 4.10","Linux >= 4.14.114 < 4.15","Linux >= 4.19.37 < 4.20","Linux >= 5.0.10 < 5.1","Linux 5.1"],"published":"2026-09-25","updated":"2026-09-25","sourceUpdated":"2026-09-25T15:17:58.933","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-97557","references":[{"url":"https://git.kernel.org/stable/c/2ed2c29dd9593637cfa25ac1eb23241b20202778","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/9f2e63f1b2d5fc5b5423424902c091123e220e7e","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/af0193bbf1ac8c0f67f972998b0cc629d6116cf6","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/dfe7b750c7e069873a8a57a11c816831a235618a","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"tags":["nvd","cve.org"],"ingestedAt":"2026-09-25T11:06:38.917Z","slug":"CVE-2026-97557","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: avoid leaking refcount in cifs_queue_oplock_break()\n\ncifs_queue_oplock_break() unconditionally takes a reference on the\ntarget file before queueing cifs_oplock_break(). Only that work item\ndecreases the reference counter again.\n\nIf another oplock break arrives while that work is still queued,\nqueue_work() will return false and not queue this second work item. As a\nresult, we will never reach the point to drop the file reference again\nand are leaking this reference. This can be triggered when interacting\nwith a slow-responding server.\n\nAs a result, later unmount operations for this file system will fail with\n\n  BUG: Dentry ... still in use (1) [unmount of cifs cifs]\n  VFS: Busy inodes after unmount of cifs (cifs)\n  kernel BUG at fs/super.c:777!\n\nFix this by only incrementing the reference count if the work has been\nqueued successfully. Taking it after queue_work() is safe because all\nthree callers hold tcon->open_file_lock across the call and\n_cifsFileInfo_put() decrements under that same lock, so a worker that\nstarts the handler in the window cannot drop the reference before it has\nbeen taken.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":41,"depthScoreParts":{"impact":41.3,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[{"seq":211000,"id":"CVE-2026-97557","ts":1790349122677,"field":"cvss","old":null,"new":"7.5"},{"seq":210999,"id":"CVE-2026-97557","ts":1790349122677,"field":"severity","old":"none","new":"high"}]}