CVE-2021-47388: mac80211: fix use-after-free in CCMP/GCMP RX

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% 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: mac80211: fix use-after-free in CCMP/GCMP RX When PN checking is done in mac80211, for fragmentation we need to copy the PN to the RX struct so we can later use it to do a comparison, since commit bf30ca922a0c ("mac80211: check defrag PN against current frame"). Unfortunately, in that commit I used the 'hdr' variable without it being necessarily valid, so use-after-free could occur if it was necessary to reallocate (parts of) the frame. Fix this by reloading the variable after the code that results in the reallocations, if any. This fixes https://bugzilla.kernel.org/show_bug.cgi?id=214401.

Affected products

Linux kernel: from 4.4.271 before 4.4.286; from 4.9.271 before 4.9.285; from 4.14.235 before 4.14.249; from 4.19.193 before 4.19.209; from 5.4.124 before 5.4.151; from 5.10.42 before 5.10.71 — fixed in 4.14.249, 4.19.209, 4.4.286, 4.9.285, 5.10.71, 5.14.10

How to fix

Upgrade to a fixed version: Linux kernel 4.14.249, 4.19.209, 4.4.286, 4.9.285. Check the vendor advisory for mitigations.

References

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