{"id":"CVE-2026-74488","summary":"wifi: mwifiex: use the subframe length when parsing A-MSDU TDLS frames","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nwifi: mwifiex: use the subframe length when parsing A-MSDU TDLS frames\n\nmwifiex_11n_dispatch_amsdu_pkt() splits an A-MSDU with\nieee80211_amsdu_to_8023s() and walks the resulting subframes. For each\nsubframe it passes the subframe data pointer to\nmwifiex_process_tdls_action_frame(), but pairs it with skb-\u003elen, the\nlength of the A-MSDU parent, instead of rx_skb-\u003elen:\n\n\trx_skb = __skb_dequeue(&list);\n\trx_hdr = (struct rx_packet_hdr *)rx_skb-\u003edata;\n\tif (ISSUPP_TDLS_ENABLED(priv-\u003eadapter-\u003efw_cap_info) &&\n\t    ntohs(rx_hdr-\u003eeth803_hdr.h_proto) == ETH_P_TDLS) {\n\t\tmwifiex_process_tdls_action_frame(priv, (u8 *)rx_hdr,\n\t\t\t\t\t\t  skb-\u003elen);\n\t}\n\nThe parent is not a valid description of that buffer, and may not be\nvalid memory at all. ieee80211_amsdu_to_8023s() ends with\n\n\tif (!reuse_skb)\n\t\tdev_kfree_skb(skb);\n\nand it only sets reuse_skb when the parent is linear, is not a\nhead_frag, and is being consumed as the *last* subframe. So when the\nparent does not qualify for reuse it has already been freed, and the\nread of skb-\u003elen is a use-after-free. When it is reused, skb-\u003elen is\nthe length of the last subframe, applied to every earlier subframe,\nwhich over-states the buffer whenever an earlier subframe is shorter.\n\nThe callee cannot absorb a wrong length, because it derives its own\nceiling from the value it is given. Each frame type computes\n\n\ties_len = len - sizeof(struct ethhdr) - TDLS_*_FIX_LEN;\n\nand the element walk is then bounded entirely against that ceiling,\n\n\tfor (end = pos + ies_len; pos + 1 \u003c end; pos += 2 + pos[1]) {\n\t\tu8 ie_len = pos[1];\n\n\t\tif (pos + 2 + ie_len \u003e end)\n\t\t\tbreak;\n\nso a too-large len moves end past the end of the subframe and the walk\nreads and copies beyond it. The A-MSDU layout is chosen by the sender,\nwhich makes the difference between the last subframe and a shorter\nearlier one remotely selectable. Reaching this requires TDLS support in\nfirmware and the TDLS ethertype on the subframe.\n\nThe other caller, mwifiex_process_rx_packet(), is correct: it passes a\npointer and a length that describe the same region of the RX buffer.\n\nPass rx_skb-\u003elen, the length of the subframe actually being parsed.","modified":"2026-08-17T03:54:57.751286242Z","published":"2026-08-15T12:27:18.867Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/74xxx/CVE-2026-74488.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/25e5a3fe4f15e30f74eca42cbf3bcc3a3fbeda79"},{"type":"WEB","url":"https://git.kernel.org/stable/c/5a21ab03829cb6d2682c127f22e2b9cd63b4393f"},{"type":"WEB","url":"https://git.kernel.org/stable/c/99a948382af8a225e2d5e54a7052158cd6281cc6"},{"type":"WEB","url":"https://git.kernel.org/stable/c/c9dcfe6b8b71369e1d732e2ff622c3696a2f032c"},{"type":"WEB","url":"https://git.kernel.org/stable/c/ece2ebb34247d573142617dfc534a9dc11ba59be"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/74xxx/CVE-2026-74488.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-74488"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"776f742040ca5eb6242c60f29ac73d5752a5b621"},{"fixed":"25e5a3fe4f15e30f74eca42cbf3bcc3a3fbeda79"},{"fixed":"ece2ebb34247d573142617dfc534a9dc11ba59be"},{"fixed":"c9dcfe6b8b71369e1d732e2ff622c3696a2f032c"},{"fixed":"5a21ab03829cb6d2682c127f22e2b9cd63b4393f"},{"fixed":"99a948382af8a225e2d5e54a7052158cd6281cc6"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-74488.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"4.5.0"},{"fixed":"6.6.151"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.103"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.44"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.1.8"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-74488.json"}}],"schema_version":"1.9.0"}