CVE-2026-23444: wifi: mac80211: always free skb on ieee80211_tx_prepare_skb() failure

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-04-03 · updated 2026-10-19
Weakness: CWE-401

Description

In the Linux kernel, the following vulnerability has been resolved: wifi: mac80211: always free skb on ieee80211_tx_prepare_skb() failure ieee80211_tx_prepare_skb() has three error paths, but only two of them free the skb. The first error path (ieee80211_tx_prepare() returning TX_DROP) does not free it, while invoke_tx_handlers() failure and the fragmentation check both do. Add kfree_skb() to the first error path so all three are consistent, and remove the now-redundant frees in callers (ath9k, mt76, mac80211_hwsim) to avoid double-free. Document the skb ownership guarantee in the function's kdoc.

Affected products

Linux kernel: from 3.13.1 before 6.18.20; from 6.19 before 6.19.10; 3.13, 7.0-rc1, 7.0-rc2, 7.0-rc3, 7.0-rc4, 7.0-rc5 (+2) — fixed in 6.18.20, 6.19.10

How to fix

Upgrade to a fixed version: Linux kernel 6.18.20, 6.19.10. Check the vendor advisory for mitigations.

References

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