CVE-2026-46244Network attack vector

Firewall bypass via IPv6 transport-header offset desynchronization

Published Jun 3, 2026 · Updated Jun 3, 2026

Firewall bypass in Linux Kernel allows remote attackers to forge transport-header matches through crafted tunneled IPv6 packets. In nft_inner_parse_l2l3(), ipv6_find_hdr() finds the true transport offset across extension headers, but code overwrites it with the 40-byte base-header endpoint while retaining the discovered Layer 4 protocol. Exposure requires nftables rules using the inner expression on ingress or forwarding hooks; forged matches can admit flows the policy intended to block.

CVSS severity9.1
Critical
EPSS probability0.32%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Firewall bypass in Linux Kernel allows remote attackers to forge transport-header matches through crafted tunneled IPv6 packets. In nft_inner_parse_l2l3(), ipv6_find_hdr() finds the true transport offset across extension headers, but code overwrites it with the 40-byte base-header endpoint while retaining the discovered Layer 4 protocol. Exposure requires nftables rules using the inner expression on ingress or forwarding hooks; forged matches can admit flows the policy intended to block.

The record

CVE
CVE-2026-46244
Published
Jun 3, 2026
Updated
Jun 3, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-823, T1562.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 3, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 3, 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=3a07327d10a09379315c844c63f27941f5081e0a <689bbf48c1f45130086ae1c46ab83ea4c753c601
  2. Affected versionversion=3a07327d10a09379315c844c63f27941f5081e0a <870d59e2cf218e7418491e26bad768cb16654582
  3. Affected versionversion=3a07327d10a09379315c844c63f27941f5081e0a <b6a91f68ebfed9c38e0e9150f58a9b85da07181c
  4. Affected versionversion=3a07327d10a09379315c844c63f27941f5081e0a <c161ad9157f5a0429b5ff94d9770faf3bf48d273
  5. Affected versionversion=3a07327d10a09379315c844c63f27941f5081e0a <d0f98a3617f6ae5b1e95cde1e68e7ead4a1279ce
  6. Affected versionversion=6.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=3a07327d10a09379315c844c63f27941f5081e0a <689bbf48c1f45130086ae1c46ab83ea4c753c601; version=3a07327d10a09379315c844c63f27941f5081e0a <870d59e2cf218e7418491e26bad768cb16654582; version=3a07327d10a09379315c844c63f27941f5081e0a <b6a91f68ebfed9c38e0e9150f58a9b85da07181c; version=3a07327d10a09379315c844c63f27941f5081e0a <c161ad9157f5a0429b5ff94d9770faf3bf48d273; version=3a07327d10a09379315c844c63f27941f5081e0a <d0f98a3617f6ae5b1e95cde1e68e7ead4a1279ce; version=6.2

Published CVSS scores

7.3UbuntuCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:H
7.3Red HatCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:H
7.3Oracle LinuxCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:H
9.1Linux CNACVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

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-823Use of Out-of-range Pointer Offset
T1562.004Impair Defenses: Disable 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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