What’s Vulnerable › Vulnerabilities

CVE-2021-47232: can: j1939: fix Use-after-Free, hold skb ref while in use

• Severity: critical (CVSS 9.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.6% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2024-05-21 · updated 2026-08-04
• Weakness: CWE-416

Description

In the Linux kernel, the following vulnerability has been resolved: can: j1939: fix Use-after-Free, hold skb ref while in use This patch fixes a Use-after-Free found by the syzbot. The problem is that a skb is taken from the per-session skb queue, without incrementing the ref count. This leads to a Use-after-Free if the skb is taken concurrently from the session queue due to a CTS.

Affected products

• Linux kernel: from 5.4 before 5.4.128; from 5.5 before 5.10.46; from 5.11 before 5.12.13; 5.13-rc1, 5.13-rc2, 5.13-rc3, 5.13-rc4, 5.13-rc5, 5.13-rc6 — fixed in 5.10.46, 5.12.13, 5.4.128

How to fix

Upgrade to a fixed version: Linux kernel 5.10.46, 5.12.13, 5.4.128. Check the vendor advisory for mitigations.

References

• https://git.kernel.org/stable/c/1071065eeb33d32b7d98c2ce7591881ae7381705
• https://git.kernel.org/stable/c/2030043e616cab40f510299f09b636285e0a3678
• https://git.kernel.org/stable/c/22cba878abf646cd3a02ee7c8c2cef7afe66a256
• https://git.kernel.org/stable/c/509ab6bfdd0c76daebbad0f0af07da712116de22
• https://git.kernel.org/stable/c/1071065eeb33d32b7d98c2ce7591881ae7381705
• https://git.kernel.org/stable/c/2030043e616cab40f510299f09b636285e0a3678
• https://git.kernel.org/stable/c/22cba878abf646cd3a02ee7c8c2cef7afe66a256
• https://git.kernel.org/stable/c/509ab6bfdd0c76daebbad0f0af07da712116de22

Get alerted when CVE-2021-47232 or the next vulnerability affects your stack