{ "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-2026-43167", "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2026-43167", "idYear": 2026, "status": "PUBLISHED", "publishedAt": "2026-05-06T11:27:43.904Z", "updatedAt": "2026-05-11T22:19:04.940Z", "importedAt": "2026-10-24T01:58:08.712Z", "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": "xfrm: always flush state and policy upon NETDEV_UNREGISTER event", "summary": "In the Linux kernel, the following vulnerability has been resolved:\n\nxfrm: always flush state and policy upon NETDEV_UNREGISTER event\n\nsyzbot is reporting that \"struct xfrm_state\" refcount is leaking.\n\n unregister_netdevice: waiting for netdevsim0 to become free. Usage count = 2\n ref_tracker: netdev@ffff888052f24618 has 1/1 users at\n __netdev_tracker_alloc include/linux/netdevice.h:4400 [inline]\n netdev_tracker_alloc include/linux/netdevice.h:4412 [inline]\n xfrm_dev_state_add+0x3a5/0x1080 net/xfrm/xfrm_device.c:316\n xfrm_state_construct net/xfrm/xfrm_user.c:986 [inline]\n xfrm_add_sa+0x34ff/0x5fa0 net/xfrm/xfrm_user.c:1022\n xfrm_user_rcv_msg+0x58e/0xc00 net/xfrm/xfrm_user.c:3507\n netlink_rcv_skb+0x158/0x420 net/netlink/af_netlink.c:2550\n xfrm_netlink_rcv+0x71/0x90 net/xfrm/xfrm_user.c:3529\n netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]\n netlink_unicast+0x5aa/0x870 net/netlink/af_netlink.c:1344\n netlink_sendmsg+0x8c8/0xdd0 net/netlink/af_netlink.c:1894\n sock_sendmsg_nosec net/socket.c:727 [inline]\n __sock_sendmsg net/socket.c:742 [inline]\n ____sys_sendmsg+0xa5d/0xc30 net/socket.c:2592\n ___sys_sendmsg+0x134/0x1d0 net/socket.c:2646\n __sys_sendmsg+0x16d/0x220 net/socket.c:2678\n do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]\n do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\n\nThis is because commit d77e38e612a0 (\"xfrm: Add an IPsec hardware\noffloading API\") implemented xfrm_dev_unregister() as no-op despite\nxfrm_dev_state_add() from xfrm_state_construct() acquires a reference\nto \"struct net_device\".\nI guess that that commit expected that NETDEV_DOWN event is fired before\nNETDEV_UNREGISTER event fires, and also assumed that xfrm_dev_state_add()\nis called only if (dev->features & NETIF_F_HW_ESP) != 0.\n\nSabrina Dubroca identified steps to reproduce the same symptoms as below.\n\n echo 0 > /sys/bus/netdevsim/new_device\n dev=$(ls -1 /sys/bus/netdevsim/devices/netdevsim0/net/)\n ip xfrm state add src 192.168.13.1 dst 192.168.13.2 proto esp \\\n spi 0x1000 mode tunnel aead 'rfc4106(gcm(aes))' $key 128 \\\n offload crypto dev $dev dir out\n ethtool -K $dev esp-hw-offload off\n echo 0 > /sys/bus/netdevsim/del_device\n\nLike these steps indicate, the NETIF_F_HW_ESP bit can be cleared after\nxfrm_dev_state_add() acquired a reference to \"struct net_device\".\nAlso, xfrm_dev_state_add() does not check for the NETIF_F_HW_ESP bit\nwhen acquiring a reference to \"struct net_device\".\n\nCommit 03891f820c21 (\"xfrm: handle NETDEV_UNREGISTER for xfrm device\")\nre-introduced the NETDEV_UNREGISTER event to xfrm_dev_event(), but that\ncommit for unknown reason chose to share xfrm_dev_down() between the\nNETDEV_DOWN event and the NETDEV_UNREGISTER event.\nI guess that that commit missed the behavior in the previous paragraph.\n\nTherefore, we need to re-introduce xfrm_dev_unregister() in order to\nrelease the reference to \"struct net_device\" by unconditionally flushing\nstate and policy.", "affected": [ { "vendor": "Linux", "product": "Linux", "defaultStatus": "unaffected", "versions": [ { "version": "d77e38e612a017480157fe6d2c1422f42cb5b7e3", "status": "affected", "versionType": "git", "lessThan": "166801e49a5b5fc127b8c9e2f110f303cfddfbc3" }, { "version": "d77e38e612a017480157fe6d2c1422f42cb5b7e3", "status": "affected", "versionType": "git", "lessThan": "a3c8fede034fa27892f87c863cbd5493167d17ed" }, { "version": "d77e38e612a017480157fe6d2c1422f42cb5b7e3", "status": "affected", "versionType": "git", "lessThan": "59581778792cbaf8ad788f4a21dc663ce986050e" }, { "version": "d77e38e612a017480157fe6d2c1422f42cb5b7e3", "status": "affected", "versionType": "git", "lessThan": "8c75c455ecd3bfd2f36abf66edb7021c4fa19ec4" }, { "version": "d77e38e612a017480157fe6d2c1422f42cb5b7e3", "status": "affected", "versionType": "git", "lessThan": "4efa91a28576054aae0e6dad9cba8fed8293aef8" } ] }, { "vendor": "Linux", "product": "Linux", "defaultStatus": "affected", "versions": [ { "version": "4.12", "status": "affected" }, { "version": "0", "status": "unaffected", "versionType": "semver", "lessThan": "4.12" }, { "version": "6.6.128", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.6.*" }, { "version": "6.12.75", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.12.*" }, { "version": "6.18.16", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.18.*" }, { "version": "6.19.6", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.19.*" }, { "version": "7.0", "status": "unaffected", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*" } ] } ] } } }