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CVE Record

CVE-2025-68817: ksmbd: fix use-after-free in ksmbd_tree_connect_put under concurrency

In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix use-after-free in ksmbd_tree_connect_put under concurrency Under high concurrency, A tree-connection object (tcon) is freed on a disconnect path while another path still holds a reference and later executes *_put()/write on it.

CriticalCVSS 9.8Not KEV-listedUpdated
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Glexia's TakeAutomated analysiscritical

Security readout for executives and security teams

Plain-English summary

A concurrency flaw in the Linux kernel’s ksmbd SMB server can free a connection object while another operation still uses it. The supplied CVSS assessment rates possible confidentiality, integrity, and availability impact as critical. Systems are most concerning when ksmbd is active and reachable from untrusted networks.

Executive priority

Treat internet-reachable or broadly accessible ksmbd servers as an urgent patching priority. Identify exposed systems immediately, reduce network access, and deploy validated distribution updates. Systems not running ksmbd are lower priority, but inventory evidence should confirm that status.

Technical view

CVE-2025-68817 is a use-after-free race in ksmbd_tree_connect_put. During concurrent disconnect and reference-release activity, a tree-connection object may be freed before another path performs a put or write. The supplied CVSS 3.1 vector is 9.8: network-accessible, low complexity, unauthenticated, and requiring no user interaction.

Likely exposure

Potential exposure is limited to Linux systems using the affected ksmbd implementation. Priority rises where SMB service is enabled and network-reachable. The bundle’s affected-version data contains unusual entries and commit hashes, so distribution-specific package status should be confirmed rather than inferred solely from version strings.

Exploitation context

The bundle marks this CVE as absent from KEV and provides no evidence of active exploitation or a public exploit. The race requires concurrent activity, but the supplied CVSS assessment indicates a remote, unauthenticated attack surface. Reliable exploitation details and real-world prevalence are not established by these sources.

Researcher notes

The core condition is a lifetime-management race between disconnect and reference-release paths involving a tree-connection object. The bundle does not identify a CWE, demonstrate code execution, or establish exploitation reliability. Review the referenced stable commits for branch-specific fixes and confirm backports through distribution advisories.

Mitigation direction

  • Apply Linux distribution updates that incorporate the referenced stable-kernel fixes.
  • Check vendor advisories for the corrected kernel package applicable to each system.
  • Disable ksmbd where it is unnecessary, following vendor-supported procedures.
  • Restrict SMB exposure to trusted networks until remediation is confirmed.

Validation and detection

  • Inventory systems running kernels listed as affected in the CVE record.
  • Confirm whether ksmbd is enabled, active, and reachable from untrusted networks.
  • Verify installed kernels contain the applicable referenced stable fix.
  • Re-scan after updates and confirm systems booted into the corrected kernel.
Prepared
Confidence
medium
Sources
8

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

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CVE-2025-68817 mapping review

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Vulnerability profileCVE Program record
Severity
Critical
CVSS
9.8 (3.1)
Known Exploited
No
Published

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

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

1CVSS vectors
3Timeline events
0ADP providers
7Source links

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
9.8CVSS 3.1CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H3.95.9Linux

Vulnerability scoring details

Base CVSS 3.1 score

9.8Critical
CVSS 3.1 vector shape for CVE-2025-68817Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

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

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinuxdd45db4d9bbc8f122a9b4db5ce94ae29fcf03d3c, 7b58ee8d0b91359554cf219cd4f33872ea2afd66, 33b235a6e6ebe0f05f3586a71e8d281d00f71e2e, 33b235a6e6ebe0f05f3586a71e8d281d00f71e2e, 33b235a6e6ebe0f05f3586a71e8d281d00f71e2e, 33b235a6e6ebe0f05f3586a71e8d281d00f71e2e, 5.15.145, 6.1.71unaffected
LinuxLinux6.6, 0, 5.15.199, 6.1.160, 6.6.120, 6.12.64, 6.18.3, 6.19affected
Weakness

CWE details

No CWE listed

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