{"id":"CVE-2026-97556","state":"PUBLISHED","title":"smb: client: avoid leaking refcount when cifs_sb_tlink() fails","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: avoid leaking refcount when cifs_sb_tlink() fails\n\ncifs_oplock_break() takes over the reference that\ncifs_queue_oplock_break() acquired when it queued the work, and drops it\nwith _cifsFileInfo_put() once the break has been processed.\n\nOnly in setups with \"-o multiuser\", cifs_sb_tlink() may fail, at which\npoint cifs_oplock_break() returns without putting the file reference,\nmirroring the reference leak we already fixed in the companion patch to\ncifs_queue_oplock_break().\n\nThis would trigger a crash due to busy inodes on the next unmount:\n\n  BUG: Dentry ... still in use (1) [unmount of cifs cifs]\n  VFS: Busy inodes after unmount of cifs (cifs)\n\nDrop the reference on that path as well. Doing so before the out label\nmirrors the normal path, which also puts the reference before\ncifs_done_oplock_break().\n\nFound by Sashiko code review. The failure path was not exercised at\nruntime.","publishedAt":"2026-09-25T10:21:47.078Z","updatedAt":"2026-10-30T12:37:21.053Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"b99f490ea87ebcca3a429fd8837067feb56a4c7c","status":"affected","lessThan":"f1fd8a84181b3af03c508e0b02b4877945dd070a","versionType":"git"},{"version":"5ee28bcfbaacf289eb25c662a2862542ea6ce6a7","status":"affected","lessThan":"55c5f095d4df14271b238f826e1392fda7b6e60e","versionType":"git"},{"version":"e8f5f849ffce24490eb9449e98312b66c0dba76f","status":"affected","lessThan":"e9c5bcc88b8337157e480c85a6d2f326bc265012","versionType":"git"},{"version":"e8f5f849ffce24490eb9449e98312b66c0dba76f","status":"affected","lessThan":"9ec991e148368e3207e98134c509a625097f7693","versionType":"git"},{"version":"e8f5f849ffce24490eb9449e98312b66c0dba76f","status":"affected","lessThan":"dd03fd658ea59821505e0e643b6b7cbdf51c4e1d","versionType":"git"},{"version":"e8f5f849ffce24490eb9449e98312b66c0dba76f","status":"affected","lessThan":"1d1b0f1d812a4011a57bc6c70492c34a2e46c6dd","versionType":"git"},{"version":"e8f5f849ffce24490eb9449e98312b66c0dba76f","status":"affected","lessThan":"23b26f4408ac3f35a482d2e5cf6fc865d4201b71","versionType":"git"},{"version":"6b67a6d2e50634fe127e656147c81915955e9f5e","status":"affected","versionType":"git"},{"version":"5.15.128","status":"affected","lessThan":"5.15.224","versionType":"semver"},{"version":"6.1.47","status":"affected","lessThan":"6.1.189","versionType":"semver"},{"version":"6.4.12","status":"affected","lessThan":"6.5","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/smb/client/file.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.5","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.5","versionType":"semver"},{"version":"5.15.224","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.189","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.158","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.111","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.53","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.7","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/smb/client/file.c"]}],"references":["https://git.kernel.org/stable/c/f1fd8a84181b3af03c508e0b02b4877945dd070a","https://git.kernel.org/stable/c/55c5f095d4df14271b238f826e1392fda7b6e60e","https://git.kernel.org/stable/c/e9c5bcc88b8337157e480c85a6d2f326bc265012","https://git.kernel.org/stable/c/9ec991e148368e3207e98134c509a625097f7693","https://git.kernel.org/stable/c/dd03fd658ea59821505e0e643b6b7cbdf51c4e1d","https://git.kernel.org/stable/c/1d1b0f1d812a4011a57bc6c70492c34a2e46c6dd","https://git.kernel.org/stable/c/23b26f4408ac3f35a482d2e5cf6fc865d4201b71"],"weaknesses":[],"ingestedAt":"2026-10-30T12:56:04.490Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/97xxx/CVE-2026-97556.json","commit":"1f312381e38164a43607eebab851b151dd16861e","baselineCommit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-97556","state":"PUBLISHED","datePublished":"2026-09-25T10:21:47.078Z","dateUpdated":"2026-10-30T12:37:21.053Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-09-24T16:01:01.154Z"},"containers":{"cna":{"title":"smb: client: avoid leaking refcount when cifs_sb_tlink() fails","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: avoid leaking refcount when cifs_sb_tlink() fails\n\ncifs_oplock_break() takes over the reference that\ncifs_queue_oplock_break() acquired when it queued the work, and drops it\nwith _cifsFileInfo_put() once the break has been processed.\n\nOnly in setups with \"-o multiuser\", cifs_sb_tlink() may fail, at which\npoint cifs_oplock_break() returns without putting the file reference,\nmirroring the reference leak we already fixed in the companion patch to\ncifs_queue_oplock_break().\n\nThis would trigger a crash due to busy inodes on the next unmount:\n\n  BUG: Dentry ... still in use (1) [unmount of cifs cifs]\n  VFS: Busy inodes after unmount of cifs (cifs)\n\nDrop the reference on that path as well. Doing so before the out label\nmirrors the normal path, which also puts the reference before\ncifs_done_oplock_break().\n\nFound by Sashiko code review. The failure path was not exercised at\nruntime."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"b99f490ea87ebcca3a429fd8837067feb56a4c7c","status":"affected","lessThan":"f1fd8a84181b3af03c508e0b02b4877945dd070a","versionType":"git"},{"version":"5ee28bcfbaacf289eb25c662a2862542ea6ce6a7","status":"affected","lessThan":"55c5f095d4df14271b238f826e1392fda7b6e60e","versionType":"git"},{"version":"e8f5f849ffce24490eb9449e98312b66c0dba76f","status":"affected","lessThan":"e9c5bcc88b8337157e480c85a6d2f326bc265012","versionType":"git"},{"version":"e8f5f849ffce24490eb9449e98312b66c0dba76f","status":"affected","lessThan":"9ec991e148368e3207e98134c509a625097f7693","versionType":"git"},{"version":"e8f5f849ffce24490eb9449e98312b66c0dba76f","status":"affected","lessThan":"dd03fd658ea59821505e0e643b6b7cbdf51c4e1d","versionType":"git"},{"version":"e8f5f849ffce24490eb9449e98312b66c0dba76f","status":"affected","lessThan":"1d1b0f1d812a4011a57bc6c70492c34a2e46c6dd","versionType":"git"},{"version":"e8f5f849ffce24490eb9449e98312b66c0dba76f","status":"affected","lessThan":"23b26f4408ac3f35a482d2e5cf6fc865d4201b71","versionType":"git"},{"version":"6b67a6d2e50634fe127e656147c81915955e9f5e","status":"affected","versionType":"git"},{"version":"5.15.128","status":"affected","lessThan":"5.15.224","versionType":"semver"},{"version":"6.1.47","status":"affected","lessThan":"6.1.189","versionType":"semver"},{"version":"6.4.12","status":"affected","lessThan":"6.5","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/smb/client/file.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.5","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.5","versionType":"semver"},{"version":"5.15.224","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.189","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.158","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.111","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.53","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.7","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/smb/client/file.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/f1fd8a84181b3af03c508e0b02b4877945dd070a"},{"url":"https://git.kernel.org/stable/c/55c5f095d4df14271b238f826e1392fda7b6e60e"},{"url":"https://git.kernel.org/stable/c/e9c5bcc88b8337157e480c85a6d2f326bc265012"},{"url":"https://git.kernel.org/stable/c/9ec991e148368e3207e98134c509a625097f7693"},{"url":"https://git.kernel.org/stable/c/dd03fd658ea59821505e0e643b6b7cbdf51c4e1d"},{"url":"https://git.kernel.org/stable/c/1d1b0f1d812a4011a57bc6c70492c34a2e46c6dd"},{"url":"https://git.kernel.org/stable/c/23b26f4408ac3f35a482d2e5cf6fc865d4201b71"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-30T12:37:21.053Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.15.128","versionEndExcluding":"5.15.224"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.1.47","versionEndExcluding":"6.1.189"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.5","versionEndExcluding":"6.6.158"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.5","versionEndExcluding":"6.12.111"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.5","versionEndExcluding":"6.18.53"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.5","versionEndExcluding":"7.2.7"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.5","versionEndExcluding":"7.3"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.4.12"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}