CVE-2024-56645Public exploitNetwork attack vector

Kernel crash via missing initial skb reference

Published Dec 27, 2024 · Updated Aug 5, 2026

Memory-safety failure in the Linux kernel J1939 transport allows remote attackers to crash the kernel through crafted session traffic. The j1939_session_new() function queues the initial sk_buff without the skb_get() reference acquired for later buffers, so teardown underflows its reference count. Reachability requires an active CAN J1939 socket and crafted transport-session traffic; public testing demonstrated repeated kernel refcount warnings and crashes.

CVSS severity9.8
Critical
EPSS probability0.68%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Memory-safety failure in the Linux kernel J1939 transport allows remote attackers to crash the kernel through crafted session traffic. The j1939_session_new() function queues the initial sk_buff without the skb_get() reference acquired for later buffers, so teardown underflows its reference count. Reachability requires an active CAN J1939 socket and crafted transport-session traffic; public testing demonstrated repeated kernel refcount warnings and crashes.

The record

CVE
CVE-2024-56645
Published
Dec 27, 2024
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499
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

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=5.4
  2. Affected versionversion=9d71dd0c70099914fcd063135da3c580865e924c <224e606a8d8e8c7db94036272c47a37455667313
  3. Affected versionversion=9d71dd0c70099914fcd063135da3c580865e924c <4199dd78a59896e091d3a7a05a77451aa7fd724d
  4. Affected versionversion=9d71dd0c70099914fcd063135da3c580865e924c <426d94815e12b6bdb9a75af294fbbafb9301601d
  5. Affected versionversion=9d71dd0c70099914fcd063135da3c580865e924c <68fceb143b635cdc59fed3896d5910aff38f345e
  6. Affected versionversion=9d71dd0c70099914fcd063135da3c580865e924c <a8c695005bfe6569acd73d777ca298ddddd66105
  7. Affected versionversion=9d71dd0c70099914fcd063135da3c580865e924c <b3282c2bebeeb82ceec492ee4972f51ee7a4a132
  8. Affected versionversion=9d71dd0c70099914fcd063135da3c580865e924c <f117cba69cbbd496babb3defcdf440df4fd6fe14

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=5.4; version=9d71dd0c70099914fcd063135da3c580865e924c <224e606a8d8e8c7db94036272c47a37455667313; version=9d71dd0c70099914fcd063135da3c580865e924c <4199dd78a59896e091d3a7a05a77451aa7fd724d; version=9d71dd0c70099914fcd063135da3c580865e924c <426d94815e12b6bdb9a75af294fbbafb9301601d; version=9d71dd0c70099914fcd063135da3c580865e924c <68fceb143b635cdc59fed3896d5910aff38f345e; version=9d71dd0c70099914fcd063135da3c580865e924c <a8c695005bfe6569acd73d777ca298ddddd66105; version=9d71dd0c70099914fcd063135da3c580865e924c <b3282c2bebeeb82ceec492ee4972f51ee7a4a132; version=9d71dd0c70099914fcd063135da3c580865e924c <f117cba69cbbd496babb3defcdf440df4fd6fe14

Published CVSS scores

7.8SUSECVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
9.8Linux Kernel CNACVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
7.1OracleCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/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.

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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 exploitPublished

Weakness, pattern, technique

T1499Endpoint Denial of Service

Public exploit references

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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