CVE-2023-4622: Use-after-free in Linux kernel's af_unix component

Severity: high (CVSS 7.0 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: 2023-09-06 · updated 2026-09-17
Weakness: CWE-416

Description

A use-after-free vulnerability in the Linux kernel's af_unix component can be exploited to achieve local privilege escalation. The unix_stream_sendpage() function tries to add data to the last skb in the peer's recv queue without locking the queue. Thus there is a race where unix_stream_sendpage() could access an skb locklessly that is being released by garbage collection, resulting in use-after-free. We recommend upgrading past commit 790c2f9d15b594350ae9bca7b236f2b1859de02c (or backported equivalents).

Affected products

Debian Linux: 10.0, 12.0
Linux kernel: from 4.2 before 4.14.324; from 4.15 before 4.19.293; from 4.20 before 5.4.255; from 5.5 before 5.10.192; from 5.11 before 5.15.128; from 5.16 before 6.1.47 — fixed in 4.14.324, 4.19.293, 5.10.192, 5.15.128, 5.4.255, 6.1.47

How to fix

Upgrade to a fixed version: Linux kernel 4.14.324, 4.19.293, 5.10.192, 5.15.128. Check the vendor advisory for mitigations.

References

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