CVE-2026-97556smb: client: avoid leaking refcount when cifs_sb_tlink() fails
- —Not scoredno CVSS score yet
- 0.21%Exploitation in 30 daysEPSS · top 89% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
In the Linux kernel, the following vulnerability has been resolved: smb: client: avoid leaking refcount when cifs_sb_tlink() fails cifs_oplock_break() takes over the reference that cifs_queue_oplock_break() acquired when it queued the work, and drops it with _cifsFileInfo_put() once the break has been processed. Only in setups with "-o multiuser", cifs_sb_tlink() may fail, at which point cifs_oplock_break() returns without putting the file reference, mirroring the reference leak we already fixed in the companion patch to cifs_queue_oplock_break(). This would trigger a crash due to busy inodes on the next unmount: BUG: Dentry ... still in use (1) [unmount of cifs cifs] VFS: Busy inodes after unmount of cifs (cifs) Drop the reference on that path as well. Doing so before the out label mirrors the normal path, which also puts the reference before cifs_done_oplock_break(). Found by Sashiko code review. The failure path was not exercised at runtime.
Timeline
ID reserved
By Linux
- 1 day later
· 1 day later
Published
- 35 days later
· 35 days later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
No CVSS score yet: neither the CNA, CISA nor NVD has scored this CVE. NVD status: Received.
- EPSS (exploitation in 30 days)
- 0.21% · top 89% of all CVEs (14 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: Not scored.
Affected products
- affected b99f490ea87ebcca3a429fd8837067feb56a4c7c – < f1fd8a84181b3af03c508e0b02b4877945dd070a
- affected 5ee28bcfbaacf289eb25c662a2862542ea6ce6a7 – < 55c5f095d4df14271b238f826e1392fda7b6e60e
- affected e8f5f849ffce24490eb9449e98312b66c0dba76f – < e9c5bcc88b8337157e480c85a6d2f326bc265012
- affected e8f5f849ffce24490eb9449e98312b66c0dba76f – < 9ec991e148368e3207e98134c509a625097f7693
- affected e8f5f849ffce24490eb9449e98312b66c0dba76f – < dd03fd658ea59821505e0e643b6b7cbdf51c4e1d
- affected e8f5f849ffce24490eb9449e98312b66c0dba76f – < 1d1b0f1d812a4011a57bc6c70492c34a2e46c6dd
- affected e8f5f849ffce24490eb9449e98312b66c0dba76f – < 23b26f4408ac3f35a482d2e5cf6fc865d4201b71
- affected 6b67a6d2e50634fe127e656147c81915955e9f5e
- affected 5.15.128 – < 5.15.224
- affected 6.1.47 – < 6.1.189
- affected 6.4.12 – < 6.5
- affected 6.5
- unaffected < 6.5
- unaffected 5.15.224 – ≤ 5.15.*
- unaffected 6.1.189 – ≤ 6.1.*
- unaffected 6.6.158 – ≤ 6.6.*
- unaffected 6.12.111 – ≤ 6.12.*
- unaffected 6.18.53 – ≤ 6.18.*
- unaffected 7.2.7 – ≤ 7.2.*
- unaffected 7.3 – ≤ *
References
References7
- https://git.kernel.org/stable/c/f1fd8a84181b3af03c508e0b02b4877945dd070a (opens in a new tab)
- https://git.kernel.org/stable/c/55c5f095d4df14271b238f826e1392fda7b6e60e (opens in a new tab)
- https://git.kernel.org/stable/c/e9c5bcc88b8337157e480c85a6d2f326bc265012 (opens in a new tab)
- https://git.kernel.org/stable/c/9ec991e148368e3207e98134c509a625097f7693 (opens in a new tab)
- https://git.kernel.org/stable/c/dd03fd658ea59821505e0e643b6b7cbdf51c4e1d (opens in a new tab)
- https://git.kernel.org/stable/c/1d1b0f1d812a4011a57bc6c70492c34a2e46c6dd (opens in a new tab)
- https://git.kernel.org/stable/c/23b26f4408ac3f35a482d2e5cf6fc865d4201b71 (opens in a new tab)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-86864 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2026-97556)Record last updated .