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CVE Record

CVE-2025-38306: fs/fhandle.c: fix a race in call of has_locked_children()

In the Linux kernel, the following vulnerability has been resolved: fs/fhandle.c: fix a race in call of has_locked_children() may_decode_fh() is calling has_locked_children() while holding no locks. That's an oopsable race... The rest of the callers are safe since they are holding namespace_sem and are guaranteed a positive refcount on the mount in question. Rename the current has_locked_children() to __has_locked_children(), make it static and switch the fs/namespace.c users to it. Make has_locked_children() a wrapper for __has_locked_children(), calling the latter under read_seqlock_excl(&mount_lock).

HighCVSS 7.8Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

A low-privileged local user may trigger a race in Linux mount and file-handle processing. The documented consequence is a kernel oops, which can disrupt affected systems. The supplied CVSS score is 7.8, but the source bundle does not establish remote reachability or active exploitation.

Executive priority

Treat as a high-priority kernel maintenance issue on affected multi-user or untrusted-workload systems. Schedule prompt patching through normal emergency-change controls where local users are not fully trusted. Remote-only systems with tightly controlled local access may be handled through accelerated routine patching after exposure confirmation.

Technical view

may_decode_fh() called has_locked_children() without the locking used by other callers, creating an oopsable race involving mount state. The correction introduces a wrapper that invokes the internal check while holding read_seqlock_excl(&mount_lock). The CVSS vector indicates local access, low complexity, low privileges, and no user interaction.

Likely exposure

Exposure requires an affected Linux kernel and local low-privileged access. The bundle lists affected releases including 6.11, 6.12.46, 6.15.3, and 6.16, but its version data is ambiguous and includes an unexplained “0”; confirm status through the relevant distribution or kernel vendor.

Exploitation context

The source bundle marks this CVE as absent from KEV and provides no cited evidence of active exploitation. This does not prove exploitation is impossible. The stated attack vector is local, so internet exposure alone is not sufficient; shared, multi-user, or otherwise locally accessible systems warrant greater attention.

Researcher notes

The description substantiates an unlocked call and an oopsable race; it does not describe demonstrated code execution or exploitation. Although the CVSS vector assigns high confidentiality, integrity, and availability impacts, the supplied narrative directly confirms only the race and potential kernel oops. Exact affected ranges require vendor verification.

Mitigation direction

  • Install the applicable vendor kernel update containing the race-condition fix.
  • Confirm the update incorporates one of the referenced stable commits or an equivalent backport.
  • Restrict unnecessary local accounts and untrusted workload access until patched.
  • Follow distribution-specific guidance where packaged kernel versions obscure upstream version mapping.

Validation and detection

  • Inventory running kernel versions and their distribution-specific build identifiers.
  • Compare each build against vendor advisories and the referenced stable commits.
  • Verify patched systems booted into the updated kernel, not an older installed image.
  • Review kernel logs for related oops events while recognizing their absence does not prove safety.
Prepared
Confidence
medium
Sources
5

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-2025-38306 mapping review

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Vulnerability profileCVE Program record
Severity
High
CVSS
7.8 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:L/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
4Source 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
7.8CVSS 3.1HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H1.85.9Linux

Vulnerability scoring details

Base CVSS 3.1 score

7.8High
CVSS 3.1 vector shape for CVE-2025-38306Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:L/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
LinuxLinux620c266f394932e5decc4b34683a75dfc59dc2f4, 620c266f394932e5decc4b34683a75dfc59dc2f4, 620c266f394932e5decc4b34683a75dfc59dc2f4unaffected
LinuxLinux6.11, 0, 6.12.46, 6.15.3, 6.16affected
Weakness

CWE details

No CWE listed

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