{ "schemaVersion": 1, "attribution": [ { "source": "CISA Known Exploited Vulnerabilities", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog", "licence": "US government work" }, { "source": "GitHub Advisory Database", "url": "https://github.com/advisories", "licence": "CC BY 4.0" }, { "source": "Have I Been Pwned", "url": "https://haveibeenpwned.com/", "licence": "CC BY 4.0" }, { "source": "CVE Program (CVE records)", "url": "https://www.cve.org/Legal/TermsOfUse", "licence": "CVE Terms of Use", "notice": "Copyright © 1999-2026, The MITRE Corporation. CVE is a trademark and the CVE logo is a registered trademark of The MITRE Corporation.", "terms": "CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE™). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy." }, { "source": "FIRST EPSS", "url": "https://www.first.org/epss/", "licence": "free to use; FIRST requests attribution" } ], "record": { "id": "CVE-2026-23340", "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2026-23340", "idYear": 2026, "status": "PUBLISHED", "publishedAt": "2026-03-25T10:27:28.728Z", "updatedAt": "2026-10-19T18:35:41.889Z", "importedAt": "2026-10-24T01:58:02.025Z", "snapshot": { "id": "cve_2026-10-24_midnight_baseline", "at": "2026-10-24T00:00:00.000Z", "source": "https://github.com/CVEProject/cvelistV5/releases/tag/cve_2026-10-24_0100Z" }, "facts": { "title": "net: sched: avoid qdisc_reset_all_tx_gt() vs dequeue race for lockless qdiscs", "summary": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: sched: avoid qdisc_reset_all_tx_gt() vs dequeue race for lockless qdiscs\n\nWhen shrinking the number of real tx queues,\nnetif_set_real_num_tx_queues() calls qdisc_reset_all_tx_gt() to flush\nqdiscs for queues which will no longer be used.\n\nqdisc_reset_all_tx_gt() currently serializes qdisc_reset() with\nqdisc_lock(). However, for lockless qdiscs, the dequeue path is\nserialized by qdisc_run_begin/end() using qdisc->seqlock instead, so\nqdisc_reset() can run concurrently with __qdisc_run() and free skbs\nwhile they are still being dequeued, leading to UAF.\n\nThis can easily be reproduced on e.g. virtio-net by imposing heavy\ntraffic while frequently changing the number of queue pairs:\n\n iperf3 -ub0 -c $peer -t 0 &\n while :; do\n ethtool -L eth0 combined 1\n ethtool -L eth0 combined 2\n done\n\nWith KASAN enabled, this leads to reports like:\n\n BUG: KASAN: slab-use-after-free in __qdisc_run+0x133f/0x1760\n ...\n Call Trace:\n \n ...\n __qdisc_run+0x133f/0x1760\n __dev_queue_xmit+0x248f/0x3550\n ip_finish_output2+0xa42/0x2110\n ip_output+0x1a7/0x410\n ip_send_skb+0x2e6/0x480\n udp_send_skb+0xb0a/0x1590\n udp_sendmsg+0x13c9/0x1fc0\n ...\n \n\n Allocated by task 1270 on cpu 5 at 44.558414s:\n ...\n alloc_skb_with_frags+0x84/0x7c0\n sock_alloc_send_pskb+0x69a/0x830\n __ip_append_data+0x1b86/0x48c0\n ip_make_skb+0x1e8/0x2b0\n udp_sendmsg+0x13a6/0x1fc0\n ...\n\n Freed by task 1306 on cpu 3 at 44.558445s:\n ...\n kmem_cache_free+0x117/0x5e0\n pfifo_fast_reset+0x14d/0x580\n qdisc_reset+0x9e/0x5f0\n netif_set_real_num_tx_queues+0x303/0x840\n virtnet_set_channels+0x1bf/0x260 [virtio_net]\n ethnl_set_channels+0x684/0xae0\n ethnl_default_set_doit+0x31a/0x890\n ...\n\nSerialize qdisc_reset_all_tx_gt() against the lockless dequeue path by\ntaking qdisc->seqlock for TCQ_F_NOLOCK qdiscs, matching the\nserialization model already used by dev_reset_queue().\n\nAdditionally clear QDISC_STATE_NON_EMPTY after reset so the qdisc state\nreflects an empty queue, avoiding needless re-scheduling.", "affected": [ { "vendor": "Linux", "product": "Linux", "defaultStatus": "unaffected", "versions": [ { "version": "6b3ba9146fe64b9bebb6346c9dcfe3b4851de2d7", "status": "affected", "versionType": "git", "lessThan": "5bb27ad54d12de67e457d7d251198e361bef835e" }, { "version": "6b3ba9146fe64b9bebb6346c9dcfe3b4851de2d7", "status": "affected", "versionType": "git", "lessThan": "7594467c49bfc2f4644dee0415ac2290db11fa0d" }, { "version": "6b3ba9146fe64b9bebb6346c9dcfe3b4851de2d7", "status": "affected", "versionType": "git", "lessThan": "dbd58b0730aa06ab6ad26079cf9a5b6b58e7e750" }, { "version": "6b3ba9146fe64b9bebb6346c9dcfe3b4851de2d7", "status": "affected", "versionType": "git", "lessThan": "5bc4e69306ed7ae02232eb4c0b23ed621a26d504" }, { "version": "6b3ba9146fe64b9bebb6346c9dcfe3b4851de2d7", "status": "affected", "versionType": "git", "lessThan": "8314944cc3bdeaa5a73e6f8a8cf0d94822e625cb" }, { "version": "6b3ba9146fe64b9bebb6346c9dcfe3b4851de2d7", "status": "affected", "versionType": "git", "lessThan": "c69df4e0524f8de8e176ba389acd83e85f5f49d0" }, { "version": "6b3ba9146fe64b9bebb6346c9dcfe3b4851de2d7", "status": "affected", "versionType": "git", "lessThan": "7f083faf59d14c04e01ec05a7507f036c965acf8" } ] }, { "vendor": "Linux", "product": "Linux", "defaultStatus": "affected", "versions": [ { "version": "4.16", "status": "affected" }, { "version": "0", "status": "unaffected", "versionType": "semver", "lessThan": "4.16" }, { "version": "5.15.203", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "5.15.*" }, { "version": "6.1.167", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.1.*" }, { "version": "6.6.130", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.6.*" }, { "version": "6.12.77", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.12.*" }, { "version": "6.18.17", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.18.*" }, { "version": "6.19.7", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.19.*" }, { "version": "7.0", "status": "unaffected", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*" } ] } ] } } }