{"id":"AZL-96240","summary":"CVE-2026-74488 affecting package kernel 6.6.150.1-1","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":"2026-09-02T06:51:55Z","published":"2026-08-15T13:17:53Z","upstream":["CVE-2026-74488"],"references":[{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-74488"}],"affected":[{"package":{"name":"kernel","ecosystem":"Azure Linux:3","purl":"pkg:rpm/azure-linux/kernel"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"6.6.150.1-1"}]}],"database_specific":{"source":"https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-96240.json"}}],"schema_version":"1.9.0"}