Vulnerability-Lookup

FKIE_CVE-2026-31444

Vulnerability from fkie_nvd - Published: 2026-04-22 14:16 - Updated: 2026-05-07 19:26

Severity

9.8 (Critical) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Summary

In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix use-after-free and NULL deref in smb_grant_oplock() smb_grant_oplock() has two issues in the oplock publication sequence: 1) opinfo is linked into ci->m_op_list (via opinfo_add) before add_lease_global_list() is called. If add_lease_global_list() fails (kmalloc returns NULL), the error path frees the opinfo via __free_opinfo() while it is still linked in ci->m_op_list. Concurrent m_op_list readers (opinfo_get_list, or direct iteration in smb_break_all_levII_oplock) dereference the freed node. 2) opinfo->o_fp is assigned after add_lease_global_list() publishes the opinfo on the global lease list. A concurrent find_same_lease_key() can walk the lease list and dereference opinfo->o_fp->f_ci while o_fp is still NULL. Fix by restructuring the publication sequence to eliminate post-publish failure: - Set opinfo->o_fp before any list publication (fixes NULL deref). - Preallocate lease_table via alloc_lease_table() before opinfo_add() so add_lease_global_list() becomes infallible after publication. - Keep the original m_op_list publication order (opinfo_add before lease list) so concurrent opens via same_client_has_lease() and opinfo_get_list() still see the in-flight grant. - Use opinfo_put() instead of __free_opinfo() on err_out so that the RCU-deferred free path is used. This also requires splitting add_lease_global_list() to take a preallocated lease_table and changing its return type from int to void, since it can no longer fail.

References

URL	Tags
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/48623ec358c1c600fa1e38368746f933e0f1a617	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/6d7e5a918c1d0aad06db0e17677b66fc9a471021	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/7de55bba69cbf0f9280daaea385daf08bc076121	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/9e785f004cbc56390479b77375726ea9b0d1a8a6	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/a5c6f6d6ceefed2d5210ee420fb75f8362461f46	Patch

Impacted products

Vendor	Product	Version
linux	linux_kernel	*
linux	linux_kernel	*
linux	linux_kernel	*
linux	linux_kernel	6.6.130
linux	linux_kernel	7.0
linux	linux_kernel	7.0

JSON

To clipboard

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      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: fix use-after-free and NULL deref in smb_grant_oplock()\n\nsmb_grant_oplock() has two issues in the oplock publication sequence:\n\n1) opinfo is linked into ci-\u003em_op_list (via opinfo_add) before\n   add_lease_global_list() is called.  If add_lease_global_list()\n   fails (kmalloc returns NULL), the error path frees the opinfo\n   via __free_opinfo() while it is still linked in ci-\u003em_op_list.\n   Concurrent m_op_list readers (opinfo_get_list, or direct iteration\n   in smb_break_all_levII_oplock) dereference the freed node.\n\n2) opinfo-\u003eo_fp is assigned after add_lease_global_list() publishes\n   the opinfo on the global lease list.  A concurrent\n   find_same_lease_key() can walk the lease list and dereference\n   opinfo-\u003eo_fp-\u003ef_ci while o_fp is still NULL.\n\nFix by restructuring the publication sequence to eliminate post-publish\nfailure:\n\n- Set opinfo-\u003eo_fp before any list publication (fixes NULL deref).\n- Preallocate lease_table via alloc_lease_table() before opinfo_add()\n  so add_lease_global_list() becomes infallible after publication.\n- Keep the original m_op_list publication order (opinfo_add before\n  lease list) so concurrent opens via same_client_has_lease() and\n  opinfo_get_list() still see the in-flight grant.\n- Use opinfo_put() instead of __free_opinfo() on err_out so that\n  the RCU-deferred free path is used.\n\nThis also requires splitting add_lease_global_list() to take a\npreallocated lease_table and changing its return type from int to void,\nsince it can no longer fail."
    }
  ],
  "id": "CVE-2026-31444",
  "lastModified": "2026-05-07T19:26:08.510",
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          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 9.8,
          "baseSeverity": "CRITICAL",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 5.9,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
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  "published": "2026-04-22T14:16:38.010",
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      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
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      "url": "https://git.kernel.org/stable/c/48623ec358c1c600fa1e38368746f933e0f1a617"
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  "weaknesses": [
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          "value": "CWE-416"
        }
      ],
      "source": "nvd@nist.gov",
      "type": "Primary"
    }
  ]
}

CVE-2026-31444 (GCVE-0-2026-31444)

Vulnerability from cvelistv5 – Published: 2026-04-22 13:53 – Updated: 2026-05-11 22:08

Title

ksmbd: fix use-after-free and NULL deref in smb_grant_oplock()

Summary

Severity

9.8 (Critical)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Assigner

Linux

References

5 references

URL	Tags
https://git.kernel.org/stable/c/9e785f004cbc56390…
https://git.kernel.org/stable/c/7de55bba69cbf0f92…
https://git.kernel.org/stable/c/a5c6f6d6ceefed2d5…
https://git.kernel.org/stable/c/6d7e5a918c1d0aad0…
https://git.kernel.org/stable/c/48623ec358c1c600f…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 302fef75512b2c8329a3f5efab1ae7ba2562387a , < 9e785f004cbc56390479b77375726ea9b0d1a8a6 (git) Affected: 08aa9f3c8cf4d0bee44df540dfe34e8d64069f2c , < 7de55bba69cbf0f9280daaea385daf08bc076121 (git) Affected: 1d6abf145615dbfe267ce3b0a271f95e3780e18e , < a5c6f6d6ceefed2d5210ee420fb75f8362461f46 (git) Affected: ce8507ee82c888126d8e7565e27c016308d24cde , < 6d7e5a918c1d0aad06db0e17677b66fc9a471021 (git) Affected: 1dfd062caa165ec9d7ee0823087930f3ab8a6294 , < 48623ec358c1c600fa1e38368746f933e0f1a617 (git)
Linux	Linux	Affected: 6.6.130 , < 6.6.131 (semver) Affected: 6.12.78 , < 6.12.80 (semver) Affected: 6.18.19 , < 6.18.21 (semver) Affected: 6.19.9 , < 6.19.11 (semver)

Show details on NVD website

JSON

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Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

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FKIE_CVE-2026-31444

CVE-2026-31444 (GCVE-0-2026-31444)

Tags

Sightings

Nomenclature