CVE-2024-56644Network attack vector

Service interruption via leaked IPv6 route references

Published Dec 27, 2024 · Updated Aug 5, 2026

IPv6 route-cache leakage in affected Linux kernels allows remote attackers to block network-namespace teardown through timed TCP and ICMPv6 traffic. ip6_negative_advice() calls dst_hold() before sk_dst_reset(), counteracting the reference decrement and orphaning an expired exception dst. Exploitation requires an ICMPv6 MTU-change packet, a timing-out TCP connection using that route, and execution after expiry but before FIB6 garbage collection.

CVSS severity7.5
High
EPSS probability0.69%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

IPv6 route-cache leakage in affected Linux kernels allows remote attackers to block network-namespace teardown through timed TCP and ICMPv6 traffic. ip6_negative_advice() calls dst_hold() before sk_dst_reset(), counteracting the reference decrement and orphaning an expired exception dst. Exploitation requires an ICMPv6 MTU-change packet, a timing-out TCP connection using that route, and execution after expiry but before FIB6 garbage collection.

The record

CVE
CVE-2024-56644
Published
Dec 27, 2024
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 27, 2024CVE 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=2.6.33.2 <2.6.34
  2. Affected versionversion=2.6.34
  3. Affected versionversion=54c1a859efd9fd6cda05bc700315ba2519c14eba <0b8903e6c881f72c6849d4952de742c656eb5ab9
  4. Affected versionversion=54c1a859efd9fd6cda05bc700315ba2519c14eba <3301ab7d5aeb0fe270f73a3d4810c9d1b6a9f045
  5. Affected versionversion=54c1a859efd9fd6cda05bc700315ba2519c14eba <535add1e9f274502209cb997801208bbe1ae6c6f
  6. Affected versionversion=54c1a859efd9fd6cda05bc700315ba2519c14eba <8b591bd522b71c42a82898290e35d32b482047e4
  7. Affected versionversion=54c1a859efd9fd6cda05bc700315ba2519c14eba <a95808252e8acc0123bacd2dff8b9af10bc145b7
  8. Affected versionversion=54c1a859efd9fd6cda05bc700315ba2519c14eba <b90d061345bb8cd51fece561a800bae1c95448a6
  9. Affected versionversion=54c1a859efd9fd6cda05bc700315ba2519c14eba <f43d12fd0fa8ee5b9caf8a3927e10d06431764d2
  10. Affected versionversion=9c93e9c757c7d3d96027a06b9b4c4e37ca87ded7

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=2.6.33.2 <2.6.34; version=2.6.34; version=54c1a859efd9fd6cda05bc700315ba2519c14eba <0b8903e6c881f72c6849d4952de742c656eb5ab9; version=54c1a859efd9fd6cda05bc700315ba2519c14eba <3301ab7d5aeb0fe270f73a3d4810c9d1b6a9f045; version=54c1a859efd9fd6cda05bc700315ba2519c14eba <535add1e9f274502209cb997801208bbe1ae6c6f; version=54c1a859efd9fd6cda05bc700315ba2519c14eba <8b591bd522b71c42a82898290e35d32b482047e4; version=54c1a859efd9fd6cda05bc700315ba2519c14eba <a95808252e8acc0123bacd2dff8b9af10bc145b7; version=54c1a859efd9fd6cda05bc700315ba2519c14eba <b90d061345bb8cd51fece561a800bae1c95448a6; version=54c1a859efd9fd6cda05bc700315ba2519c14eba <f43d12fd0fa8ee5b9caf8a3927e10d06431764d2; version=9c93e9c757c7d3d96027a06b9b4c4e37ca87ded7

Published CVSS scores

7.5kernel.orgCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
5.5Canonical UbuntuCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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

T1499.004Application 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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