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CVE Record

CVE-2022-48974: netfilter: conntrack: fix using __this_cpu_add in preemptible

In the Linux kernel, the following vulnerability has been resolved: netfilter: conntrack: fix using __this_cpu_add in preemptible Currently in nf_conntrack_hash_check_insert(), when it fails in nf_ct_ext_valid_pre/post(), NF_CT_STAT_INC() will be called in the preemptible context, a call trace can be triggered: BUG: using __this_cpu_add() in preemptible [00000000] code: conntrack/1636 caller is nf_conntrack_hash_check_insert+0x45/0x430 [nf_conntrack] Call Trace: <TASK> dump_stack_lvl+0x33/0x46 check_preemption_disabled+0xc3/0xf0 nf_conntrack_hash_check_insert+0x45/0x430 [nf_conntrack] ctnetlink_create_conntrack+0x3cd/0x4e0 [nf_conntrack_netlink] ctnetlink_new_conntrack+0x1c0/0x450 [nf_conntrack_netlink] nfnetlink_rcv_msg+0x277/0x2f0 [nfnetlink] netlink_rcv_skb+0x50/0x100 nfnetlink_rcv+0x65/0x144 [nfnetlink] netlink_unicast+0x1ae/0x290 netlink_sendmsg+0x257/0x4f0 sock_sendmsg+0x5f/0x70 This patch is to fix it by changing to use NF_CT_STAT_INC_ATOMIC() for nf_ct_ext_valid_pre/post() check in nf_conntrack_hash_check_insert(), as well as nf_ct_ext_valid_post() in __nf_conntrack_confirm(). Note that nf_ct_ext_valid_pre() check in __nf_conntrack_confirm() is safe to use NF_CT_STAT_INC(), as it's under local_bh_disable().

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

This is a Linux kernel reliability flaw in netfilter connection tracking. During specific conntrack validation failure paths, the kernel can update per-CPU statistics from a preemptible context and trigger a kernel BUG trace. Business impact depends on whether affected systems run netfilter conntrack.

Executive priority

Treat as a targeted Linux kernel maintenance issue, not confirmed emergency exploitation. Prioritize infrastructure where conntrack failure could disrupt network services or security controls, and rely on vendor-patched kernels.

Technical view

nf_conntrack_hash_check_insert() and __nf_conntrack_confirm() could call NF_CT_STAT_INC(), which uses __this_cpu_add(), during nf_ct_ext_valid_pre/post() failure handling in unsafe contexts. The fix changes those paths to NF_CT_STAT_INC_ATOMIC(), while preserving the non-atomic path where local_bh_disable() already applies.

Likely exposure

Exposure is limited to Linux systems running affected kernel versions with netfilter connection tracking paths in use. The source bundle lists Linux kernel 5.19, 6.0.13, and 6.1-related version data, but distro backport status must be checked separately.

Exploitation context

The provided sources do not show active exploitation, KEV listing, public exploit activity, or a weaponized attack path. The evidence shows a kernel BUG trace reachable through conntrack/netlink-related code paths when validation fails.

Researcher notes

The public record is sparse: no CVSS, CWE, or exploit status is provided. Analysis should focus on affected kernel lineage, distro backports, and whether local conntrack/netlink functionality is reachable in the environment.

Mitigation direction

  • Check vendor kernel advisories for patched or backported fixes.
  • Upgrade to a kernel build containing the referenced stable fixes.
  • Prioritize internet-facing firewalls, routers, NAT gateways, and Kubernetes nodes using conntrack.
  • Track distribution-specific package names and reboot requirements.

Validation and detection

  • Inventory kernel versions across Linux hosts and appliances.
  • Confirm whether nf_conntrack and nf_conntrack_netlink are loaded or used.
  • Compare installed kernels against vendor advisories and stable fix commits.
  • Review kernel logs for related __this_cpu_add preemptible BUG traces.
Prepared
Confidence
medium
Sources
4

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

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CVE-2022-48974 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
1ADP providers
3Source 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

CISA-ADPCISA ADP Vulnrichment
other:ssvc

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinuxc56716c69ce1ac320432fb1ea5654196ba24d2f8, c56716c69ce1ac320432fb1ea5654196ba24d2f8unaffected
LinuxLinux5.19, 0, 6.0.13, 6.1affected
Weakness

CWE details

No CWE listed

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