wifi: mac80211: always free skb on ieee80211_tx_prepare_skb() failure

Summary

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.

Timeline

1. Apr 3, 2026, 3:15 PM UTCCVE published
2. Oct 16, 2026, 3:08 PM UTCCISA SSVC assessment

   Exploitation: none · Automatable: no · Technical impact: total

3. Oct 19, 2026, 6:35 PM UTCRecord last updated

Affected versions

• Linux Linux

  From 06be6b149f7e406bcf16098567f5a6c9f042bced · fixed in 905ef207d5ed99ca64adfe39fba9ac46e434327a; From 06be6b149f7e406bcf16098567f5a6c9f042bced · fixed in 5ef8ca1c164786da24169af155c1ca1ff1353cf8; From 06be6b149f7e406bcf16098567f5a6c9f042bced · fixed in 9a779d1f480e83720b5384adf165604e7ee226bd; From 06be6b149f7e406bcf16098567f5a6c9f042bced · fixed in f77b51bcee7be2bb686b5f7a2d4a1921e4bdb9f4; From 06be6b149f7e406bcf16098567f5a6c9f042bced · fixed in 3b4d27acafaeab478fd24f79ad6e593a892828b9; From 06be6b149f7e406bcf16098567f5a6c9f042bced · fixed in 06e769dddcbeb3baf2ce346273b53dd61fdbecf4; From 06be6b149f7e406bcf16098567f5a6c9f042bced · fixed in 50f1b690b4868923fbd242298def2fb88662f108; From 06be6b149f7e406bcf16098567f5a6c9f042bced · fixed in d5ad6ab61cbd89afdb60881f6274f74328af3ee9

• Linux Linux

  3.13

• KernelLinux

  From 3.13.0 · fixed in 5.10.258; From 5.11.0 · fixed in 5.15.209; From 5.16.0 · fixed in 6.1.175; From 6.2.0 · fixed in 6.6.136; From 6.7.0 · fixed in 6.12.84; From 6.13.0 · fixed in 6.18.20; From 6.19.0 · fixed in 6.19.10

References 8