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CVE Record

CVE-2024-40956: dmaengine: idxd: Fix possible Use-After-Free in irq_process_work_list

In the Linux kernel, the following vulnerability has been resolved: dmaengine: idxd: Fix possible Use-After-Free in irq_process_work_list Use list_for_each_entry_safe() to allow iterating through the list and deleting the entry in the iteration process. The descriptor is freed via idxd_desc_complete() and there's a slight chance may cause issue for the list iterator when the descriptor is reused by another thread without it being deleted from the list.

HighCVSS 7.8Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

A timing race in the Linux idxd DMA driver can leave kernel code using a descriptor after it has been freed. On affected systems, a lower-privileged local actor could potentially trigger kernel memory corruption, threatening confidentiality, integrity, and availability. The provided evidence does not establish remote reachability or real-world exploitation.

Executive priority

Treat this as high-priority patching for systems using idxd and hosting less-trusted local workloads. It is not presented as an internet-remote flaw, and active exploitation is not evidenced. Address it within normal expedited kernel maintenance, accelerating further where tenant isolation, sensitive data, or system availability is business-critical.

Technical view

irq_process_work_list() iterates a descriptor list while idxd_desc_complete() can free the current descriptor. Another thread may reuse it before the iterator advances, creating a use-after-free. The kernel fix uses list_for_each_entry_safe() so deletion during iteration does not invalidate traversal.

Likely exposure

Exposure is limited to Linux systems containing and using the affected idxd dmaengine code. The bundle lists several version markers and branch-specific stable fixes, but its version representation is ambiguous. Determine status from the running distribution kernel build, vendor advisory, and fix backport rather than version matching alone.

Exploitation context

CVSS 3.1 rates this 7.8: local access, low complexity, low privileges, and no user interaction. It is not in KEV, and the supplied sources do not document active exploitation. Practical reachability and reliability depend on access to the idxd driver and winning the described race.

Researcher notes

The defect is a concurrent list-deletion safety error with a narrow timing window. Source material identifies the corrective iteration primitive but provides no demonstrated exploit path, hardware prerequisites, or affected configuration details. Researchers should distinguish code presence from reachability and account for distribution backports when assessing versions.

Mitigation direction

  • Install the applicable distribution or kernel.org stable update containing the referenced idxd fix.
  • Prioritize hosts using idxd that also run untrusted or less-trusted local workloads.
  • Consult the kernel or distribution vendor for supported guidance if immediate updating is unavailable.
  • Reboot as required so the corrected kernel becomes the running kernel.

Validation and detection

  • Inventory each host's running kernel build and distribution package, not merely installed packages.
  • Determine whether the idxd dmaengine driver is configured, loaded, or actively used.
  • Confirm the running build includes an applicable referenced fix or vendor backport.
  • After updating, verify the corrected kernel is running and relevant regression tests pass.
  • Review kernel logs for idxd-related faults, while recognizing absence of faults does not prove safety.
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-2024-40956 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
2ADP providers
7Source 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
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-2024-40956Attack 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.

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
LinuxLinux16e19e11228ba660d9e322035635e7dcf160d5c2, 16e19e11228ba660d9e322035635e7dcf160d5c2, 16e19e11228ba660d9e322035635e7dcf160d5c2, 16e19e11228ba660d9e322035635e7dcf160d5c2, 16e19e11228ba660d9e322035635e7dcf160d5c2unaffected
LinuxLinux5.11, 0, 5.15.162, 6.1.96, 6.6.36, 6.9.7, 6.10affected
Weakness

CWE details

No CWE listed

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