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CVE Record

CVE-2024-35863: smb: client: fix potential UAF in is_valid_oplock_break()

In the Linux kernel, the following vulnerability has been resolved: smb: client: fix potential UAF in is_valid_oplock_break() Skip sessions that are being teared down (status == SES_EXITING) to avoid UAF.

CriticalCVSS 9.8Not KEV-listedUpdated
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Glexia's TakeAutomated analysiscritical

Security readout for executives and security teams

Plain-English summary

A race in the Linux SMB client could access memory after its session was released during teardown. A remote SMB peer may be able to trigger the condition without credentials or user interaction. The supplied CVSS rates potential confidentiality, integrity, and availability impact as high, but practical exploit outcomes are not documented in the bundle.

Executive priority

Treat as urgent for systems using the Linux SMB client with untrusted network reachability. Accelerate vendor-supported kernel updates, but avoid declaring a fleet-wide emergency solely from the 9.8 score because active exploitation is unsupported and the supplied affected-version data requires vendor interpretation.

Technical view

The function is_valid_oplock_break() could inspect a session being torn down, creating a potential use-after-free. The upstream correction skips sessions marked SES_EXITING. The supplied records associate affected Linux kernel lines with versions including 3.13, 6.1.85, 6.6.26, 6.8.5, and 6.9, but their version structure is ambiguous.

Likely exposure

Prioritize Linux systems that use the kernel SMB client to connect to remote or untrusted SMB services. Systems without SMB client use are less likely to reach the vulnerable path. The bundle provides no CPEs, and its mixed release and commit identifiers prevent reliable exposure decisions from version strings alone.

Exploitation context

The CVSS 3.1 vector describes network-reachable, low-complexity, unauthenticated exploitation without user interaction. However, CISA KEV status is false, and the supplied sources provide no evidence of exploitation in the wild or a public working exploit. Treat the score as potential severity, not confirmation of practical exploitability.

Researcher notes

The record describes a potential teardown race and UAF, fixed by ignoring SES_EXITING sessions. No CWE, CPE, crash trace, exploitability analysis, or demonstrated security consequence is supplied. Multiple stable commits appear to backport the correction. Researchers should avoid inferring arbitrary code execution from the CVSS impacts alone.

Mitigation direction

  • Install a vendor-supported kernel containing the applicable referenced stable fix.
  • Check distribution advisories for package-specific affected and corrected versions.
  • Prioritize systems connecting to remote or untrusted SMB services.
  • Restrict unnecessary SMB connectivity until affected systems are updated.

Validation and detection

  • Record each system's kernel package, release, and distribution build.
  • Check vendor advisories for CVE-2024-35863 applicability and backports.
  • Confirm whether systems use the kernel SMB client.
  • Verify the installed kernel includes the applicable stable fix.
  • Reassess SMB connectivity 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

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CVE-2024-35863 mapping review

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

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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
2ADP providers
5Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: noTechnical Impact: partial

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-2024-35863Attack 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.

ADP provider summaries

CVECVE Program Container
CISA-ADPCISA ADP Vulnrichment
other:ssvc

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux7f48558e6489d032b1584b0cc9ac4bb11072c034, 7f48558e6489d032b1584b0cc9ac4bb11072c034, 7f48558e6489d032b1584b0cc9ac4bb11072c034, 7f48558e6489d032b1584b0cc9ac4bb11072c034, a67172a013953664b1dad03c648200c70b90506c, 3.12.48unaffected
LinuxLinux3.13, 0, 6.1.85, 6.6.26, 6.8.5, 6.9affected
Weakness

CWE details

No CWE listed

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