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CVE Record

CVE-2024-40921: net: bridge: mst: pass vlan group directly to br_mst_vlan_set_state

In the Linux kernel, the following vulnerability has been resolved: net: bridge: mst: pass vlan group directly to br_mst_vlan_set_state Pass the already obtained vlan group pointer to br_mst_vlan_set_state() instead of dereferencing it again. Each caller has already correctly dereferenced it for their context. This change is required for the following suspicious RCU dereference fix. No functional changes intended.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

CVE-2024-40921 is a Linux kernel bridge/VLAN issue. The public description frames the fix as correcting an RCU dereference pattern in bridge MST code, with no intended functional change. Business urgency is unclear without severity, CVSS, or exploitation evidence.

Executive priority

Track and remediate through normal kernel patch management unless your environment relies heavily on Linux bridging. Escalate only if a vendor advisory assigns higher severity or exploitation emerges.

Technical view

The kernel fix passes an already obtained VLAN group pointer into br_mst_vlan_set_state() instead of dereferencing it again. The source says each caller already dereferenced it correctly for context, and the change supports a suspicious RCU dereference fix.

Likely exposure

Exposure is most relevant to Linux systems using kernel bridge VLAN/MST functionality. The provided data names Linux kernel commit and version identifiers, but does not provide a clear affected range. Validate against vendor and distribution kernel advisories.

Exploitation context

The source bundle does not show CISA KEV listing, public exploitation, exploit maturity, privilege requirements, or attacker path. Treat active exploitation as unconfirmed.

Researcher notes

Evidence is thin: no CVSS, CWE, exploit status, or clear affected range is provided. The commit message suggests a correctness fix around RCU-safe pointer handling rather than a documented crash, escalation, or remote attack path.

Mitigation direction

  • Inventory Linux kernels on systems using bridge VLAN or MST features.
  • Check kernel.org stable fixes and your distribution advisory for patched builds.
  • Prioritize vendor-supported kernel updates over manual backports.
  • Review Debian LTS guidance if running affected Debian LTS kernels.

Validation and detection

  • Compare running kernel versions against vendor advisory fixed versions.
  • Confirm whether bridge VLAN or MST functionality is enabled on exposed hosts.
  • Verify kernel packages include the referenced stable commits or distro backports.
  • Document exceptions where appliances or embedded systems cannot be updated.
Prepared
Confidence
medium
Sources
7

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-2024-40921 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
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.

0CVSS vectors
3Timeline events
2ADP providers
6Source links

SSVC decision data

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

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
LinuxLinux8ca9a750fc711911ef616ceb627d07357b04545e, 4488617e5e995a09abe4d81add5fb165674edb59, e43dd2b1ec746e105b7db5f9ad6ef14685a615a4, 3a7c1661ae1383364cd6092d851f5e5da64d476b, a2b01e65d9ba8af2bb086d3b7288ca53a07249ac, 6.8.12unaffected
LinuxLinux6.1.93, 6.6.33, 6.9.3unaffected
Weakness

CWE details

No CWE listed

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