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CVE Record

CVE-2024-40993: netfilter: ipset: Fix suspicious rcu_dereference_protected()

In the Linux kernel, the following vulnerability has been resolved: netfilter: ipset: Fix suspicious rcu_dereference_protected() When destroying all sets, we are either in pernet exit phase or are executing a "destroy all sets command" from userspace. The latter was taken into account in ip_set_dereference() (nfnetlink mutex is held), but the former was not. The patch adds the required check to rcu_dereference_protected() in ip_set_dereference().

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

CVE-2024-40993 is a Linux kernel netfilter ipset bug fixed in stable kernel updates. The public record describes an RCU safety check missing during ipset destruction, not a clear business impact. Treat it as kernel maintenance risk: prioritize affected internet-facing or appliance Linux systems once vendor packages are available.

Executive priority

Set priority after asset scoping. With no severity score or exploitation evidence, this is not automatically an emergency, but kernel flaws in network filtering components should be remediated through normal patch cycles, faster for appliances and critical Linux infrastructure.

Technical view

The issue is in netfilter ipset. During destroy-all-set handling, ip_set_dereference() accounted for the userspace destroy path but not the per-network-namespace exit phase. The fix adds the missing rcu_dereference_protected() condition. Sources do not provide CVSS, CWE, crash impact, privilege impact, or remote exploitability.

Likely exposure

Exposure is likely limited to Linux kernels carrying the vulnerable ipset code, especially systems or products using netfilter/ipset. Distro and appliance kernels may be backported, so raw upstream version checks are insufficient. The bundle names stable fixes including 6.1.95, 6.6.35, and 6.9.6.

Exploitation context

The source bundle does not show active exploitation, public exploit code, or KEV listing. Available references are Linux stable commits plus Debian LTS and Siemens advisories. Do not treat this as exploited unless a vendor advisory or KEV later states that.

Researcher notes

The useful technical signal is narrow: an RCU protected dereference condition was incomplete for pernet exit during ipset destruction. Public sources do not establish attacker control, prerequisites, crashability, or exploitability. Further assessment should inspect vendor patches and kernel configurations, not assume impact from the CVE title alone.

Mitigation direction

  • Upgrade to a vendor-supported kernel containing the CVE-2024-40993 fix.
  • Check Debian, Siemens, and other product advisories for backported kernel package status.
  • Prioritize systems using netfilter/ipset or embedded Linux networking functions.
  • Follow vendor guidance where fixed package names or appliance firmware versions differ from upstream versions.

Validation and detection

  • Inventory Linux kernel versions and vendor package revisions across servers and appliances.
  • Confirm whether netfilter ipset functionality is present or used on each system.
  • Verify installed kernels include the upstream fix or a vendor backport.
  • Review Debian LTS and Siemens advisories if those environments are in scope.
Prepared
Confidence
medium
Sources
11

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-2024-40993 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
3ADP providers
10Source 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
siemens-SADPADP container

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinuxc0761d1f1ce1d5b85b5e82bbb714df12de1aa8c3, 93b53c202b51a69e42ca57f5a183f7e008e19f83, 0f1bb77c6d837c9513943bc7c08f04c5cc5c6568, 390b353d1a1da3e9c6c0fd14fe650d69063c95d6, 2ba35b37f780c6410bb4bba9c3072596d8576702, 90ae20d47de602198eb69e6cd7a3db3420abfc08, 4e7aaa6b82d63e8ddcbfb56b4fd3d014ca586f10unaffected
LinuxLinux6.1.95, 6.6.35, 6.9.6unaffected
Weakness

CWE details

No CWE listed

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