{"id":"CVE-2026-64037","revision":"8d0671fb662f43a5bef9a3faf838250f","records":[{"revision":"8d0671fb662f43a5bef9a3faf838250f","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-64037","aliases":[],"title":"wifi: iwlwifi: mld: fix TSO segmentation explosion when AMSDU is disabled","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nwifi: iwlwifi: mld: fix TSO segmentation explosion when AMSDU is disabled\n\nWhen the TLC notification disables AMSDU for a TID, the MLD driver sets\nmax_tid_amsdu_len to the sentinel value 1. The TSO segmentation path in\niwl_mld_tx_tso_segment() checks for zero but not for this sentinel,\nallowing it to reach the num_subframes calculation:\n\n  num_subframes = (max_tid_amsdu_len + pad) / (subf_len + pad)\n                = (1 + 2) / (1534 + 2) = 0\n\nThis zero propagates to iwl_tx_tso_segment() which sets:\n\n  gso_size = num_subframes * mss = 0\n\nCalling skb_gso_segment() with gso_size=0 creates over 32000 tiny\nsegments from a single GSO skb. This floods the TX ring with ~1024\nmicro-frames (the rest are purged), creating a massive burst of TX\ncompletion events that can lead to memory corruption and a subsequent\nuse-after-free in TCP's retransmit queue (refcount underflow in\ntcp_shifted_skb, NULL deref in tcp_rack_detect_loss).\n\nThe MVM driver is immune because it checks mvmsta->amsdu_enabled before\nreaching the num_subframes calculation. The MLD driver has no equivalent\nbitmap check and relies solely on max_tid_amsdu_len, which does not\ncatch the sentinel value.\n\nFix this by detecting the sentinel value (max_tid_amsdu_len == 1) at the\nexisting check and falling back to non-AMSDU TSO segmentation. Also add\na WARN_ON_ONCE guard after the num_subframes division as defense-in-depth\nto catch any future code paths that produce zero through a different\nmechanism.","state":0,"publishedAt":"2026-07-19T15:39:25.435+00:00","modifiedAt":"2026-10-19T20:28:10.404+00:00","affected":[{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"unaffected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"drivers/net/wireless/intel/iwlwifi/mld/tx.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"d1e879ec600f9b3bdd253167533959facfefb17b\",\n                            \"lessThan\": \"9e360e610a73f62432e986775023d5382773f045\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"d1e879ec600f9b3bdd253167533959facfefb17b\",\n                            \"lessThan\": \"cbe1c8245e4469d1aa6e12e5d913611376d23788\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"d1e879ec600f9b3bdd253167533959facfefb17b\",\n                            \"lessThan\": \"92cee08dc4f00e77fd1317e4343c5d458b0abab7\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        }\n                    ]\n                }"},{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"affected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"drivers/net/wireless/intel/iwlwifi/mld/tx.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"6.15\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"6.15\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.18.34\",\n                            \"lessThanOrEqual\": \"6.18.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.0.11\",\n                            \"lessThanOrEqual\": \"7.0.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.1\",\n                            \"lessThanOrEqual\": \"*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"original_commit_for_fix\"\n                        }\n                    ]\n                }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","score":9.8,"severity":"CRITICAL"}],"references":["https://git.kernel.org/stable/c/9e360e610a73f62432e986775023d5382773f045","https://git.kernel.org/stable/c/cbe1c8245e4469d1aa6e12e5d913611376d23788","https://git.kernel.org/stable/c/92cee08dc4f00e77fd1317e4343c5d458b0abab7"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-64037","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-64037","identifiers":["CVE-2026-64037"]},"retained":false,"historicalAffected":[]}],"coverage":[]}