# CVE-2026-31477: CVE-2026-31477 Status: published. Published: 2026-04-22. Updated: 2026-11-11. In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix memory leaks and NULL deref in smb2_lock() smb2_lock() has three error handling issues after list_del() detaches smb_lock from lock_list at no_check_cl: 1) If vfs_lock_file() returns an unexpected error in the non-UNLOCK path, goto out leaks smb_lock and its flock because the out: handler only iterates lock_list and rollback_list, neither of which contains the detached smb_lock. 2) If vfs_lock_file() returns -ENOENT in the UNLOCK path, goto out leaks smb_lock and flock for the same reason. The error code returned to the dispatcher is also stale. 3) In the rollback path, smb_flock_init() can return NULL on allocation failure. The result is dereferenced unconditionally, causing a kernel NULL pointer dereference. Add a NULL check to prevent the crash and clean up the bookkeeping; the VFS lock itself cannot be rolled back without the allocation and will be released at file or connection teardown. Fix cases 1 and 2 by hoisting the locks_free_lock()/kfree() to before the if(!rc) check in the UNLOCK branch so all exit paths share one free site, and by freeing smb_lock and flock before goto out in the non-UNLOCK branch. Propagate the correct error code in both cases. Fix case 3 by wrapping the VFS unlock in an if(rlock) guard and adding a NULL check for locks_free_lock(rlock) in the shared cleanup. Found via call-graph analysis using sqry. ## Remediation - fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67) — https://git.kernel.org/stable/c/309b44ed684496ed3f9c5715d10b899338623512 - fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67) — https://git.kernel.org/stable/c/3cdacd11b41569ce75b3162142240f2355e04900 - fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67) — https://git.kernel.org/stable/c/91aeaa7256006d79a37298f5a1df23325db91599 - fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67) — https://git.kernel.org/stable/c/aab42f0795620cf0d3955a520f571f697d0f9a2a - fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67) — https://git.kernel.org/stable/c/c9b95ef6f5039f19e46c3a521a4fe1752d91dfe9 - fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67) — https://git.kernel.org/stable/c/cdac6f7e7e428dc70e3b5898ac6999a72ed13993 ## Affected products and versions - linux / linux_kernel: ≥ 5.15.1; < 6.1.168 (affected, custom). Source: NVD - linux / linux_kernel: ≥ 6.2; < 6.6.131 (affected, custom). Source: NVD - linux / linux_kernel: ≥ 6.7; < 6.12.80 (affected, custom). Source: NVD - linux / linux_kernel: ≥ 6.13; < 6.18.21 (affected, custom). Source: NVD - linux / linux_kernel: ≥ 6.19; < 6.19.11 (affected, custom). Source: NVD - linux / linux_kernel: 5.15 (affected, custom). Source: NVD - linux / linux_kernel: 7.0 (affected, custom). Source: NVD ## NVD configuration conditions Affected CPE matches depend on the following AND/OR and negation conditions: ```json [ { "negate": false, "nodes": [ { "cpeMatch": [ { "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionEndExcluding": "6.1.168", "versionStartIncluding": "5.15.1", "vulnerable": true }, { "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionEndExcluding": "6.6.131", "versionStartIncluding": "6.2", "vulnerable": true }, { "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionEndExcluding": "6.12.80", "versionStartIncluding": "6.7", "vulnerable": true }, { "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionEndExcluding": "6.18.21", "versionStartIncluding": "6.13", "vulnerable": true }, { "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionEndExcluding": "6.19.11", "versionStartIncluding": "6.19", "vulnerable": true }, { "criteria": "cpe:2.3:o:linux:linux_kernel:5.15:-:*:*:*:*:*:*", "vulnerable": true }, { "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:*", "vulnerable": true }, { "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:*", "vulnerable": true }, { "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc3:*:*:*:*:*:*", "vulnerable": true }, { "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc4:*:*:*:*:*:*", "vulnerable": true }, { "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc5:*:*:*:*:*:*", "vulnerable": true }, { "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc6:*:*:*:*:*:*", "vulnerable": true }, { "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc7:*:*:*:*:*:*", "vulnerable": true } ], "negate": false, "operator": "OR" } ], "operator": "OR" } ] ``` ## Severity and prioritization - CVSS 3.1: 7.5 (high); CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H; source: NVD: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 - CISA KEV: No listing in collected sources - EPSS: Not available - SSVC: Not available - Weaknesses: CWE-476 ## Exploit evidence No exploit evidence in collected sources. This is not proof of no exploitation. ## References - https://git.kernel.org/stable/c/309b44ed684496ed3f9c5715d10b899338623512 (416baaa9-dc9f-4396-8d5f-8c081fb06d67; Patch) - https://git.kernel.org/stable/c/3cdacd11b41569ce75b3162142240f2355e04900 (416baaa9-dc9f-4396-8d5f-8c081fb06d67; Patch) - https://git.kernel.org/stable/c/91aeaa7256006d79a37298f5a1df23325db91599 (416baaa9-dc9f-4396-8d5f-8c081fb06d67; Patch) - https://git.kernel.org/stable/c/aab42f0795620cf0d3955a520f571f697d0f9a2a (416baaa9-dc9f-4396-8d5f-8c081fb06d67; Patch) - https://git.kernel.org/stable/c/c9b95ef6f5039f19e46c3a521a4fe1752d91dfe9 (416baaa9-dc9f-4396-8d5f-8c081fb06d67; Patch) - https://git.kernel.org/stable/c/cdac6f7e7e428dc70e3b5898ac6999a72ed13993 (416baaa9-dc9f-4396-8d5f-8c081fb06d67; Patch) ## Provenance - NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-31477; retrieved 2026-11-12; source updated 2026-11-11 Revision: 1b78d7dbc0842e6925cfc9013b3e60a7219452846a2deefea6d9beabae1f1dcc Canonical: https://y2.dev/cve/CVE-2026-31477 ## Agent and API access Public CVE pages, Markdown, and JSON are free to read without an account or API key. - Public catalog: https://y2.dev/cve/index.json. 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