# CVE-2024-56645: can: j1939: j1939\_session\_new(): fix skb reference counting

- Severity: CVSS 9.8 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): no
- Published: 2024-12-27 · Updated: 2026-08-05

## Affected

- Linux: version range not reported
- Linux: 5.4

## Description

In the Linux kernel, the following vulnerability has been resolved: can: j1939: j1939_session_new(): fix skb reference counting Since j1939_session_skb_queue() does an extra skb_get() for each new skb, do the same for the initial one in j1939_session_new() to avoid refcount underflow. [mkl: clean up commit message]

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory per the references below.
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## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/224e606a8d8e8c7db94036272c47a37455667313
- https://git.kernel.org/stable/c/b3282c2bebeeb82ceec492ee4972f51ee7a4a132
- https://git.kernel.org/stable/c/4199dd78a59896e091d3a7a05a77451aa7fd724d
- https://git.kernel.org/stable/c/f117cba69cbbd496babb3defcdf440df4fd6fe14
- https://git.kernel.org/stable/c/426d94815e12b6bdb9a75af294fbbafb9301601d
- https://git.kernel.org/stable/c/68fceb143b635cdc59fed3896d5910aff38f345e
- https://git.kernel.org/stable/c/a8c695005bfe6569acd73d777ca298ddddd66105

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Page: https://cve.now/CVE-2024-56645
JSON: https://cve.now/api/v1/entries/CVE-2024-56645
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