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NVD / CVE Program· CNA Linux

CVE-2025-68809: ksmbd: vfs: fix race on m_flags in vfs_cache

Noroxi assessment

Priority: Monitor (action score 36/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.52% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Linux Linux 5adad9727a815c26013b0d41cfee92ffa7d4037c, 991f8a79db99b14c48d20d2052c82d65b9186cad, a4fd1fdf505facfae26b5654c9eff321f4cbc1a7; azl3 kernel 6.6.119.3-3 on Azure Linux 3.0 6.6.121.1-1.

Low priority for now. Upgrade to Linux Linux 5adad9727a815c26013b0d41cfee92ffa7d4037c, 991f8a79db99b14c48d20d2052c82d65b9186cad, a4fd1fdf505facfae26b5654c9eff321f4cbc1a7; azl3 kernel 6.6.119.3-3 on Azure Linux 3.0 6.6.121.1-1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

In the Linux kernel, the following vulnerability has been resolved: ksmbd: vfs: fix race on m_flags in vfs_cache ksmbd maintains delete-on-close and pending-delete state in ksmbd_inode->m_flags. In vfs_cache.c this field is accessed under inconsistent locking: some paths read and modify m_flags under ci->m_lock while others do so without taking the lock at all. Examples: - ksmbd_query_inode_status() and __ksmbd_inode_close() use ci->m_lock when checking or updating m_flags. - ksmbd_inode_pending_delete(), ksmbd_set_inode_pending_delete(), ksmbd_clear_inode_pending_delete() and ksmbd_fd_set_delete_on_close() used to read and modify m_flags without ci->m_lock. This creates a potential data race on m_flags when multiple threads open, close and delete the same file concurrently. In the worst case delete-on-close and pending-delete bits can be lost or observed in an inconsistent state, leading to confusing delete semantics (files that stay on disk after delete-on-close, or files that disappear while still in use). Fix it by: - Making ksmbd_query_inode_status() look at m_flags under ci->m_lock after dropping inode_hash_lock. - Adding ci->m_lock protection to all helpers that read or modify m_flags (ksmbd_inode_pending_delete(), ksmbd_set_inode_pending_delete(), ksmbd_clear_inode_pending_delete(), ksmbd_fd_set_delete_on_close()). - Keeping the existing ci->m_lock protection in __ksmbd_inode_close(), and moving the actual unlink/xattr removal outside the lock. This unifies the locking around m_flags and removes the data race while preserving the existing delete-on-close behaviour.

CriticalCVSS 9.1 · v3.1—No exploit Fix available
Published
Jan 13, 2026
Updated
Oct 30, 2026
EPSS
0.5% · 44th percentile
CWE
—

Report tools

JSON

Action score

36

Monitor

Low priority for now.

CVSS
36 / 40 · 9.1 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.5%

CNA vs NVD score

NVD
—
CNA · Linux
9.1
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

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  • No public exploit code on record
  • A fix has been released

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When you'll hear from us

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 5.15affected
    • f44158485826c076335d6860d35872271a83791d and later · before a4fd1fdf505facfae26b5654c9eff321f4cbc1a7affected · git
    • f44158485826c076335d6860d35872271a83791d and later · before 5adad9727a815c26013b0d41cfee92ffa7d4037caffected · git
    • f44158485826c076335d6860d35872271a83791d and later · before ccc78781041589ea383e61d5d7a1e9a31b210b93affected · git
    • f44158485826c076335d6860d35872271a83791d and later · before ee63729760f5b61a66f345c54dc4c7514e62383daffected · git
    • f44158485826c076335d6860d35872271a83791d and later · before 991f8a79db99b14c48d20d2052c82d65b9186cadaffected · git
    • before 5.15not affected · semver
    • 6.1.191 and later · up to and including 6.1.*not affected · semver
    • 6.6.120 and later · up to and including 6.6.*not affected · semver
    • 6.12.64 and later · up to and including 6.12.*not affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12linuxfrom 0—
Debian:13linuxbefore 6.12.69-16.12.69-1
Debian:14linuxbefore 6.18.3-16.18.3-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

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    40Plan
  • CVE-2026-74612veth: fix skb length accounting after XDP frag adjustment
    40Plan
  • CVE-2026-74475vxlan: use neigh_ha_snapshot() in route_shortcircuit()
    40Plan

Published before and after this one in the same product

  • ← EarlierCVE-2025-68801Jan 13, 2026 · mlxsw: spectrum_router: Fix neighbour use-after-free
    31Monitor
  • ← EarlierCVE-2025-68803Jan 13, 2026 · NFSD: NFSv4 file creation neglects setting ACL
    32Monitor
  • Later →CVE-2025-68811Jan 13, 2026 · svcrdma: use rc_pageoff for memcpy byte offset
    39Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux5adad9727a815c26013b0d41cfee92ffa7d4037cVendor (CNA)
Linux Linux991f8a79db99b14c48d20d2052c82d65b9186cadVendor (CNA)
Linux Linuxa4fd1fdf505facfae26b5654c9eff321f4cbc1a7Vendor (CNA)
Linux Linuxccc78781041589ea383e61d5d7a1e9a31b210b93Vendor (CNA)
Linux Linuxee63729760f5b61a66f345c54dc4c7514e62383dVendor (CNA)
azl3 kernel 6.6.119.3-3 on Azure Linux 3.06.6.121.1-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
debian:linux6.12.69-1 · Debian:13Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
High
Availability impact
High

Weakness class (CWE)

—

CVSS vector

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

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (4 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records