{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-74489", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-08-15T05:44:03.905Z", "datePublished": "2026-08-15T12:27:19.505Z", "dateUpdated": "2026-08-17T05:47:46.250Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-17T05:47:46.250Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nwifi: mac80211: fix tid_tx use-after-free on BA session stop\n\nieee80211_stop_tx_ba_cb() hands tid_tx to kfree_rcu() through\nieee80211_remove_tid_tx(), and then reads tid_tx->ndp after dropping\nsta->lock:\n\n\tieee80211_remove_tid_tx(sta, tid);\t/* kfree_rcu(tid_tx, rcu_head) */\n\t...\n\tspin_unlock_bh(&sta->lock);\n\n\tif (start_txq)\n\t\tieee80211_agg_start_txq(sta, tid, false);\n\n\tif (send_delba)\n\t\tieee80211_send_delba(..., tid_tx->ndp);\n\nThat read is not covered by an RCU read-side critical section, and it runs\nin preemptible process context: both callers hold the wiphy mutex, reaching\nit either from the ieee80211_ba_session_work() wiphy work or from\nieee80211_sta_tear_down_BA_sessions() during station teardown.\nSoftirqs can run in that window too, both from the local_bh_enable() that\nends ieee80211_agg_start_txq() and from any interrupt exit, so the RCU\ncallback can free tid_tx before the read.\n\nDriving the function from a test module with the grace period forced into\nthat window, KASAN reports the read, and the free arrives on the ordinary\nRCU softirq path:\n\n BUG: KASAN: slab-use-after-free in ieee80211_stop_tx_ba_cb+0x3cd/0x400\n Read of size 1 at addr ffff888002b9f52e by task kworker/0:1/10\n [...]\n Freed by task 57:\n __kasan_slab_free+0x47/0x70\n __rcu_free_sheaf_prepare+0x70/0x250\n rcu_free_sheaf_nobarn+0x18/0x40\n rcu_core+0x426/0x1310\n handle_softirqs+0x144/0x590\n __irq_exit_rcu+0xea/0x150\n irq_exit_rcu+0x9/0x20\n sysvec_apic_timer_interrupt+0x6b/0x80\n asm_sysvec_apic_timer_interrupt+0x1a/0x20\n\nsend_delba is only set when tx_stop is set, which happens for\nAGG_STOP_LOCAL_REQUEST alone, so this is reached on local teardown -\nsession idle timeout, PTK rekey, suspend, HW reconfig - and not from a\npeer's DELBA.\n\nRead ndp into a local before the session is freed, while sta->lock is still\nheld. tid_tx->ndp has a single writer, in\nieee80211_tx_ba_session_handle_start(), which cannot run concurrently here:\nboth paths are serialised by the wiphy mutex, and the session is already\nmarked HT_AGG_STATE_STOPPING at this point. tid_tx->ndp is also the only\ntid_tx dereference left after ieee80211_remove_tid_tx() in this function.\n\n[move/change the comment a bit to be more general not just on ndp,\n initialize ndp directly]" } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "baseScore": 8.8, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:A - The bug is in mac80211 WiFi block-ack teardown; an adjacent 802.11 peer with an active TX BA session can drive AGG_STOP_LOCAL_REQUEST via negotiated session-idle timeouts, PTK rekey, or link conditions that cause local session stop.\nAC:L - This is a slab use-after-free where RCU can free tid_tx between ieee80211_remove_tid_tx() and the post-unlock tid_tx->ndp read; the commit reproduced it reliably, and an attacker can repeatedly trigger local BA teardown to hit the race window.\nPR:N - Exploitation requires no Linux user or administrator privileges on the victim, only normal 802.11 association as a WiFi peer to maintain a block-ack session that later undergoes local teardown.\nUI:N - No victim interaction beyond routine WiFi connectivity is needed; session-idle timers, rekey, and driver-initiated local BA stop can fire from background wireless activity without the user performing a specific action.\nS:U - Impact is confined to kernel memory corruption and privilege escalation within the host kernel; it does not cross a VM, IOMMU, or sandbox security boundary.\nC:H - Reading tid_tx->ndp after kfree_rcu() is a slab use-after-free of a kernel heap object, which can disclose or infer kernel memory contents and support further exploitation primitives.\nI:H - Use-after-free of tid_ampdu_tx enables heap corruption and control of freed object contents, which can be leveraged for arbitrary kernel writes or code execution beyond the single-byte ndp read.\nA:H - The freed-object dereference can cause kernel oops/panic; KASAN reported slab-use-after-free in ieee80211_stop_tx_ba_cb during BA session stop, and UAFs in mac80211 commonly crash the system." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/mac80211/agg-tx.c" ], "versions": [ { "version": "98acd4c1d9f7dc9c426e840c16e81b57315ff84b", "lessThan": "09fc36eec7841cdf732f4db39855e0c73bd075cc", "status": "affected", "versionType": "git" }, { "version": "98acd4c1d9f7dc9c426e840c16e81b57315ff84b", "lessThan": "2f067f5a450ea07efd249142a11d940a068fe29c", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/mac80211/agg-tx.c" ], "versions": [ { "version": "7.1", "status": "affected" }, { "version": "0", "lessThan": "7.1", "status": "unaffected", "versionType": "semver" }, { "version": "7.1.8", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "7.1", "versionEndExcluding": "7.1.8" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "7.1", "versionEndExcluding": "7.2" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/09fc36eec7841cdf732f4db39855e0c73bd075cc" }, { "url": "https://git.kernel.org/stable/c/2f067f5a450ea07efd249142a11d940a068fe29c" } ], "title": "wifi: mac80211: fix tid_tx use-after-free on BA session stop", "x_generator": { "engine": "bippy-1.2.0" } } } }