LiveActive security incident?Get immediate response
CVE Record

CVE-2025-37952: ksmbd: Fix UAF in __close_file_table_ids

In the Linux kernel, the following vulnerability has been resolved: ksmbd: Fix UAF in __close_file_table_ids A use-after-free is possible if one thread destroys the file via __ksmbd_close_fd while another thread holds a reference to it. The existing checks on fp->refcount are not sufficient to prevent this. The fix takes ft->lock around the section which removes the file from the file table. This prevents two threads acquiring the same file pointer via __close_file_table_ids, as well as the other functions which retrieve a file from the IDR and which already use this same lock.

HighCVSS 8.8Not KEV-listedUpdated
Discuss exposureBack to CVEs
Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

A concurrency flaw in Linux’s ksmbd SMB server can free a file object while another thread still uses it. A network user with low privileges could potentially trigger memory corruption affecting confidentiality, integrity, or availability. Systems not running ksmbd are unlikely to be exposed through this component.

Executive priority

Prioritize exposed ksmbd servers, especially internet-accessible or broadly reachable file servers. Patch them on an accelerated schedule after operational testing. Systems where ksmbd is absent or disabled are lower priority for this CVE, but asset owners should verify that condition rather than assume it.

Technical view

CVE-2025-37952 is a use-after-free in __close_file_table_ids. Concurrent file destruction through __ksmbd_close_fd can race with a thread holding the same file reference because refcount checks are insufficient. The fix protects file-table removal with ft->lock, preventing concurrent retrieval of the same pointer. CVSS 3.1 is 8.8: network-accessible, low complexity, low privileges, and no user interaction.

Likely exposure

Exposure is concentrated in Linux systems actively using ksmbd and reachable by untrusted or lower-privileged SMB clients. The supplied record lists affected release markers including 5.15, 6.6.91, 6.12.29, 6.14.7, and 6.15, but does not provide clear distribution-specific package mappings or complete affected ranges.

Exploitation context

The supplied sources do not establish active exploitation, and the CVE is not marked as CISA KEV. The network vector, low complexity, and low-privilege requirement increase concern, but no public exploit evidence is included. Treat exploitability beyond the documented race and use-after-free as unconfirmed.

Researcher notes

The security boundary is the ksmbd file-table lifecycle. The patch serializes IDR lookup and removal using the existing ft->lock. The provided material establishes a race-driven use-after-free but does not document a proof of concept, observed exploitation, reliable impact outcome, affected configuration prerequisites, or distribution-level fixed versions.

Mitigation direction

  • Upgrade to a vendor-supported kernel containing the applicable stable fix or backport.
  • Check distribution security guidance for the exact corrected package version.
  • Disable ksmbd where SMB server functionality is unnecessary.
  • Restrict SMB access to trusted networks and authorized clients until patched.

Validation and detection

  • Determine whether ksmbd is enabled, loaded, or configured to start.
  • Identify the running kernel and distribution package version.
  • Confirm the vendor kernel includes an applicable listed stable commit or backport.
  • Verify SMB service exposure from relevant untrusted network segments.
  • Retest ksmbd availability and legitimate file-sharing workflows after remediation.
Prepared
Confidence
medium
Sources
6

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.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cve · low confidence lookup

CVE-2025-37952 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

Open ATT&CK lookup
Vulnerability profileCVE Program record
Severity
High
CVSS
8.8 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:N/AC:L/PR:L/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
5Source 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
8.8CVSS 3.1HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H2.85.9Linux

Vulnerability scoring details

Base CVSS 3.1 score

8.8High
CVSS 3.1 vector shape for CVE-2025-37952Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:N/AC:L/PR:L/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
LinuxLinux0626e6641f6b467447c81dd7678a69c66f7746cf, 0626e6641f6b467447c81dd7678a69c66f7746cf, 0626e6641f6b467447c81dd7678a69c66f7746cf, 0626e6641f6b467447c81dd7678a69c66f7746cfunaffected
LinuxLinux5.15, 0, 6.6.91, 6.12.29, 6.14.7, 6.15affected
Weakness

CWE details

No CWE listed

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.