CVE-2026-72348Network attack vector

Firewall bypass via malformed IPv6 extension headers

Published Aug 15, 2026 · Updated Aug 15, 2026

Improper length validation in Linux kernel ip6tables allows remote attackers to bypass IPv6 extension-header filtering. The AH, hop-by-hop, and routing-header matchers treat lengths beyond available packet data as ordinary rule mismatches instead of hotdrop failures. Exploitation requires reachable IPv6 traffic and ip6tables rules using the ah, hbh, or rt matches; the consequence is limited to bypass of those intended drop rules.

CVSS severity9.1
Critical
EPSS probability0.63%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper length validation in Linux kernel ip6tables allows remote attackers to bypass IPv6 extension-header filtering. The AH, hop-by-hop, and routing-header matchers treat lengths beyond available packet data as ordinary rule mismatches instead of hotdrop failures. Exploitation requires reachable IPv6 traffic and ip6tables rules using the ah, hbh, or rt matches; the consequence is limited to bypass of those intended drop rules.

The record

CVE
CVE-2026-72348
Published
Aug 15, 2026
Updated
Aug 15, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-130, T1562.004
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=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <2fd89a50a9783eed8ed23866b11c8b3d8779a7a8
  2. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <3578b6d92a5b1e603ae6e8c8f5538a709f03aba4
  3. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <3d441be2b1c5e98167302fa1c7b61960a067b112
  4. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <43ccc20b5a733226417832cf16ef45322e594990
  5. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <d5e39e5eb6b30bc4a3bb7aba54c293cf36a806c7
  6. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <f16d856b6af5fd0e7cb0b0212f70825b599ef72e
  7. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <f775fcf384b06f35b612f78fa5601fee99eb6513
  8. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <fc416870100cf16d5b9495199355a679c3a02d48
  9. Affected versionversion=2.6.12

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <2fd89a50a9783eed8ed23866b11c8b3d8779a7a8; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <3578b6d92a5b1e603ae6e8c8f5538a709f03aba4; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <3d441be2b1c5e98167302fa1c7b61960a067b112; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <43ccc20b5a733226417832cf16ef45322e594990; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <d5e39e5eb6b30bc4a3bb7aba54c293cf36a806c7; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <f16d856b6af5fd0e7cb0b0212f70825b599ef72e; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <f775fcf384b06f35b612f78fa5601fee99eb6513; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <fc416870100cf16d5b9495199355a679c3a02d48; version=2.6.12

Published CVSS scores

9.1Linux CNACVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
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-130Improper Handling of Length Parameter Inconsistency
T1562.004Disable or Modify System Firewall

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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