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CVE Record

CVE-2024-40996: bpf: Avoid splat in pskb_pull_reason

In the Linux kernel, the following vulnerability has been resolved: bpf: Avoid splat in pskb_pull_reason syzkaller builds (CONFIG_DEBUG_NET=y) frequently trigger a debug hint in pskb_may_pull. We'd like to retain this debug check because it might hint at integer overflows and other issues (kernel code should pull headers, not huge value). In bpf case, this splat isn't interesting at all: such (nonsensical) bpf programs are typically generated by a fuzzer anyway. Do what Eric suggested and suppress such warning. For CONFIG_DEBUG_NET=n we don't need the extra check because pskb_may_pull will do the right thing: return an error without the WARN() backtrace.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

This CVE describes a Linux kernel issue where nonsensical BPF programs can trigger a debug warning backtrace in networking code. The provided sources do not state data theft, privilege escalation, denial of service impact, CVSS, or active exploitation. Treat it as a kernel maintenance item unless your vendor assigns higher severity.

Executive priority

Handle through normal kernel patch management. Escalate only for exposed custom or debug kernels, or if your distribution later publishes a higher-severity advisory.

Technical view

The issue is in the BPF path around pskb_pull_reason and pskb_may_pull. With CONFIG_DEBUG_NET enabled, oversized or invalid pull requests can produce a WARN backtrace. The fix suppresses this unhelpful BPF-triggered warning while relying on pskb_may_pull to return an error when CONFIG_DEBUG_NET is disabled.

Likely exposure

Exposure is limited to Linux systems running affected kernel branches or downstream kernels that have not backported the referenced stable fixes. Systems with BPF enabled may be relevant, but the sources do not define a practical attacker model or required privileges.

Exploitation context

The bundle says syzkaller frequently triggers this in debug-networking builds and describes such BPF programs as fuzzer-generated. It does not cite exploitation in the wild, and KEV is false. No weaponized exploit evidence is provided.

Researcher notes

Evidence points to warning suppression in a BPF/networking edge case rather than a clearly described exploitable memory-safety flaw. The CVE record lists affected and fixed kernel branches, but the provided sources do not include CVSS, CWE, exploitability analysis, or attacker prerequisites.

Mitigation direction

  • Check your Linux distribution advisory for CVE-2024-40996 coverage.
  • Update to a vendor kernel containing the referenced stable fixes.
  • Prioritize debug or test kernels built with CONFIG_DEBUG_NET.
  • Track Debian LTS guidance if using Debian-packaged kernels.

Validation and detection

  • Inventory Linux kernel versions across production, test, and CI systems.
  • Confirm whether vendor kernel changelogs mention CVE-2024-40996 or the stable commits.
  • Identify systems using custom kernels or debug networking builds.
  • Verify patched kernels are running after reboot, not merely installed.
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-2024-40996 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
LinuxLinux8af60bb2b215f478b886f1d6d302fefa7f0b917d, 1b2b26595bb09febf14c5444c873ac4ec90a5a77, 219eee9c0d16f1b754a8b85275854ab17df0850a, 219eee9c0d16f1b754a8b85275854ab17df0850a, fff05b2b004d9a8a2416d08647f3dc9068e357c8, 6.1.86, 6.6.27, 6.8.6unaffected
LinuxLinux6.9, 0, 6.1.96, 6.6.36, 6.9.7, 6.10affected
Weakness

CWE details

No CWE listed

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