CVE-2026-72251Network attack vector

Kernel memory corruption via stale SIP packet pointer

Published Aug 15, 2026 · Updated Aug 15, 2026

Expired-pointer use in the Linux kernel SIP NAT helper allows attackers to corrupt packet headers when cloned buffers are reallocated. The nf_nat_sip function calls skb_ensure_writable(), which can replace a cloned SKB buffer, but leaves dptr referencing the freed allocation. The SIP conntrack helper must process a cloned packet; the stale pointer can corrupt headers, manipulate the wrong packet data, or interrupt service.

CVSS severity9.8
Critical
EPSS probability0.71%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Expired-pointer use in the Linux kernel SIP NAT helper allows attackers to corrupt packet headers when cloned buffers are reallocated. The nf_nat_sip function calls skb_ensure_writable(), which can replace a cloned SKB buffer, but leaves dptr referencing the freed allocation. The SIP conntrack helper must process a cloned packet; the stale pointer can corrupt headers, manipulate the wrong packet data, or interrupt service.

The record

CVE
CVE-2026-72251
Published
Aug 15, 2026
Updated
Aug 15, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-825, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 15, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 15, 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=3.9
  2. Affected versionversion=7266507d89991fa1e989283e4e032c6d9357fe26 <0e76e3e886cc9ee027337d5ad39cb96f57b7bdc7
  3. Affected versionversion=7266507d89991fa1e989283e4e032c6d9357fe26 <2bcf2c5052fb5e73e255140ab43f056aef409c27
  4. Affected versionversion=7266507d89991fa1e989283e4e032c6d9357fe26 <57e4e29644ec054d7021d296407e7ddd844afea2
  5. Affected versionversion=7266507d89991fa1e989283e4e032c6d9357fe26 <77e43bcb7ec177e293a5c3f1b91a2c5aebfb6c68
  6. Affected versionversion=7266507d89991fa1e989283e4e032c6d9357fe26 <bded21a4bf9bf86a79148be735723a97ca9a7532
  7. Affected versionversion=7266507d89991fa1e989283e4e032c6d9357fe26 <dc11f26685aa850f237226f0f463647aea58ab7c
  8. Affected versionversion=7266507d89991fa1e989283e4e032c6d9357fe26 <e38143c9b477f2968024c47c647dd4456a40aff1
  9. Affected versionversion=7266507d89991fa1e989283e4e032c6d9357fe26 <eae9c6ccb5af69c713a65f8ae219f5c1aa32cd17

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=3.9; version=7266507d89991fa1e989283e4e032c6d9357fe26 <0e76e3e886cc9ee027337d5ad39cb96f57b7bdc7; version=7266507d89991fa1e989283e4e032c6d9357fe26 <2bcf2c5052fb5e73e255140ab43f056aef409c27; version=7266507d89991fa1e989283e4e032c6d9357fe26 <57e4e29644ec054d7021d296407e7ddd844afea2; version=7266507d89991fa1e989283e4e032c6d9357fe26 <77e43bcb7ec177e293a5c3f1b91a2c5aebfb6c68; version=7266507d89991fa1e989283e4e032c6d9357fe26 <bded21a4bf9bf86a79148be735723a97ca9a7532; version=7266507d89991fa1e989283e4e032c6d9357fe26 <dc11f26685aa850f237226f0f463647aea58ab7c; version=7266507d89991fa1e989283e4e032c6d9357fe26 <e38143c9b477f2968024c47c647dd4456a40aff1; version=7266507d89991fa1e989283e4e032c6d9357fe26 <eae9c6ccb5af69c713a65f8ae219f5c1aa32cd17

Published CVSS scores

9.8Linux kernel CVE CNACVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
7.0Amazon LinuxCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:H
7.0Oracle LinuxCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
7.0Red HatCVSS:3.1/AV:L/AC:H/PR:L/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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-825Expired Pointer Dereference
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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