CVE-2025-38472Network attack vector

Kernel crash via premature conntrack confirmation

Published Jul 28, 2025 · Updated Aug 5, 2026

Race condition in Linux nf_conntrack allows remote attackers to crash the kernel through concurrent processing of UDP flows. nf_conntrack_confirm sets IPS_CONFIRMED before a recycled nf_conn entry is inserted into the hash table, allowing expiration handling to unlink an uninitialized list node. The race requires an expired entry, reuse on another CPU, and an insertion-skipping path; successful triggering causes a kernel crash rather than a persistent data change.

CVSS severity9.8
Critical
EPSS probability0.39%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Race condition in Linux nf_conntrack allows remote attackers to crash the kernel through concurrent processing of UDP flows. nf_conntrack_confirm sets IPS_CONFIRMED before a recycled nf_conn entry is inserted into the hash table, allowing expiration handling to unlink an uninitialized list node. The race requires an expired entry, reuse on another CPU, and an insertion-skipping path; successful triggering causes a kernel crash rather than a persistent data change.

The record

CVE
CVE-2025-38472
Published
Jul 28, 2025
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 28, 2025CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=1397af5bfd7d32b0cf2adb70a78c9a9e8f11d912 <2d72afb340657f03f7261e9243b44457a9228ac7
  2. Affected versionversion=1397af5bfd7d32b0cf2adb70a78c9a9e8f11d912 <76179961c423cd698080b5e4d5583cf7f4fcdde9
  3. Affected versionversion=1397af5bfd7d32b0cf2adb70a78c9a9e8f11d912 <938ce0e8422d3793fe30df2ed0e37f6bc0598379
  4. Affected versionversion=1397af5bfd7d32b0cf2adb70a78c9a9e8f11d912 <a47ef874189d47f934d0809ae738886307c0ea22
  5. Affected versionversion=1397af5bfd7d32b0cf2adb70a78c9a9e8f11d912 <fc38c249c622ff5e3011b8845fd49dbfd9289afc
  6. Affected versionversion=5.18.13 <5.19
  7. Affected versionversion=5.19
  8. Affected versionversion=594cea2c09f7cd440d1ee1c4547d5bc6a646b0e4

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=1397af5bfd7d32b0cf2adb70a78c9a9e8f11d912 <2d72afb340657f03f7261e9243b44457a9228ac7; version=1397af5bfd7d32b0cf2adb70a78c9a9e8f11d912 <76179961c423cd698080b5e4d5583cf7f4fcdde9; version=1397af5bfd7d32b0cf2adb70a78c9a9e8f11d912 <938ce0e8422d3793fe30df2ed0e37f6bc0598379; version=1397af5bfd7d32b0cf2adb70a78c9a9e8f11d912 <a47ef874189d47f934d0809ae738886307c0ea22; version=1397af5bfd7d32b0cf2adb70a78c9a9e8f11d912 <fc38c249c622ff5e3011b8845fd49dbfd9289afc; version=5.18.13 <5.19; version=5.19; version=594cea2c09f7cd440d1ee1c4547d5bc6a646b0e4

Published CVSS scores

9.8LinuxCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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