llc: fix skb UAF and leaks on llc_mac_hdr_init() failure

Summary

In the Linux kernel, the following vulnerability has been resolved: llc: fix skb UAF and leaks on llc_mac_hdr_init() failure In llc_conn_ac_resend_i_xxx_x_set_0_or_send_rr(), if llc_mac_hdr_init() fails, kfree_skb(skb) is called instead of kfree_skb(nskb). This leaks the newly allocated nskb, reads from the freed skb via LLC_I_GET_NR(pdu), and double-frees skb when llc_conn_state_process() drops its reference. In llc_sap_action_send_xid_r() and llc_sap_action_send_test_r(), nskb is leaked if llc_mac_hdr_init() returns an error. Free nskb in all three error paths.

Timeline

1. Oct 18, 2026, 3:18 PM UTCCVE published
2. Oct 24, 2026, 2:09 PM UTCRecord last updated

Affected versions

• Linux Linux

  From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in fec0fe6838a7f45175667701fb51abb23a6ffb1e; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in b859ba18b5a1067f71db5618c6a4a70d55fa308b; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in 8b855b645841b5a04e20339a22bb6d593c9b790d; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in d360b31f1a3666579422872aa7d1a751e20b76f9; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in 060f827aa3dc47939ee306da715cd6700d129616; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in 41dcae82bece9f106b4dff0ee777bba8d157c8a8; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in cb3528ad8bb46fa6252f5d14ced7febddc18515d; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in 72f9dd522f8d6c5a00be9695c7bb74631eb5069e

• Linux Linux

  2.6.12

• KernelLinux

  From 2.6.12 · fixed in 5.10.271; From 5.11.0 · fixed in 5.15.222; From 5.16.0 · fixed in 6.1.189; From 6.2.0 · fixed in 6.6.158; From 6.7.0 · fixed in 6.12.112; From 6.13.0 · fixed in 6.18.55; From 6.19.0 · fixed in 7.2.9

References 8