CVE-2026-63924Network attack vector

Remote kernel memory corruption via stale IPv6 pointer

Published Jul 19, 2026 · Updated Jul 19, 2026

Use-after-free in Linux kernel IPv6 extension-header parsing allows remote attackers to corrupt kernel memory via crafted IPv6 packets. In ipv6_parse_hopopts, ipv6_hop_jumbo() can relocate the packet buffer through pskb_trim_rcsum(), but parsing continues through an unrefreshed network-header pointer. Remote attackers need only deliver IPv6 Hop-by-Hop options containing a Jumbo Payload TLV to disclose or corrupt kernel memory or cause a kernel panic.

CVSS severity9.8
Critical
EPSS probability0.71%
Next 30 days · Sep 17, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in Linux kernel IPv6 extension-header parsing allows remote attackers to corrupt kernel memory via crafted IPv6 packets. In ipv6_parse_hopopts, ipv6_hop_jumbo() can relocate the packet buffer through pskb_trim_rcsum(), but parsing continues through an unrefreshed network-header pointer. Remote attackers need only deliver IPv6 Hop-by-Hop options containing a Jumbo Payload TLV to disclose or corrupt kernel memory or cause a kernel panic.

The record

CVE
CVE-2026-63924
Published
Jul 19, 2026
Updated
Jul 19, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 19, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 19, 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 <2b56bbd928c030894c270cd33d60286326919458
  2. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <645b99b1a185c91a79bdac4c5de0f91b212d64f0
  3. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <72af7beae774e46ed543f3f2f267bf0a141bfcdd
  4. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <9e883eaa878f4337b5873c706efb5a192364ed18
  5. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <b3ac54e5c905f86d22b502eacb5686a282c5659f
  6. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <bddaa4dfc7f36e1ee343a0622f69288af2b9ace9
  7. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <c512e1c819dfbf6ae95ee7a44b65b9ad98979157
  8. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <d47548a36639095939f4747d4c43f2271366f565
  9. Affected versionversion=2.6.12

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <2b56bbd928c030894c270cd33d60286326919458; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <645b99b1a185c91a79bdac4c5de0f91b212d64f0; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <72af7beae774e46ed543f3f2f267bf0a141bfcdd; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <9e883eaa878f4337b5873c706efb5a192364ed18; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <b3ac54e5c905f86d22b502eacb5686a282c5659f; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <bddaa4dfc7f36e1ee343a0622f69288af2b9ace9; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <c512e1c819dfbf6ae95ee7a44b65b9ad98979157; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <d47548a36639095939f4747d4c43f2271366f565; version=2.6.12

Published CVSS scores

9.8kernel.orgCVSS: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 11, 2026Sep 17, 2026
Latest reporting daySep 17, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499.004Endpoint Denial of Service: Application or System Exploitation

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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