{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2022-50697", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-12-24T10:53:15.517Z", "datePublished": "2025-12-24T10:55:13.762Z", "dateUpdated": "2026-08-05T08:59:24.625Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T08:59:24.625Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmrp: introduce active flags to prevent UAF when applicant uninit\n\nThe caller of del_timer_sync must prevent restarting of the timer, If\nwe have no this synchronization, there is a small probability that the\ncancellation will not be successful.\n\nAnd syzbot report the fellowing crash:\n==================================================================\nBUG: KASAN: use-after-free in hlist_add_head include/linux/list.h:929 [inline]\nBUG: KASAN: use-after-free in enqueue_timer+0x18/0xa4 kernel/time/timer.c:605\nWrite at addr f9ff000024df6058 by task syz-fuzzer/2256\nPointer tag: [f9], memory tag: [fe]\n\nCPU: 1 PID: 2256 Comm: syz-fuzzer Not tainted 6.1.0-rc5-syzkaller-00008-\nge01d50cbd6ee #0\nHardware name: linux,dummy-virt (DT)\nCall trace:\n dump_backtrace.part.0+0xe0/0xf0 arch/arm64/kernel/stacktrace.c:156\n dump_backtrace arch/arm64/kernel/stacktrace.c:162 [inline]\n show_stack+0x18/0x40 arch/arm64/kernel/stacktrace.c:163\n __dump_stack lib/dump_stack.c:88 [inline]\n dump_stack_lvl+0x68/0x84 lib/dump_stack.c:106\n print_address_description mm/kasan/report.c:284 [inline]\n print_report+0x1a8/0x4a0 mm/kasan/report.c:395\n kasan_report+0x94/0xb4 mm/kasan/report.c:495\n __do_kernel_fault+0x164/0x1e0 arch/arm64/mm/fault.c:320\n do_bad_area arch/arm64/mm/fault.c:473 [inline]\n do_tag_check_fault+0x78/0x8c arch/arm64/mm/fault.c:749\n do_mem_abort+0x44/0x94 arch/arm64/mm/fault.c:825\n el1_abort+0x40/0x60 arch/arm64/kernel/entry-common.c:367\n el1h_64_sync_handler+0xd8/0xe4 arch/arm64/kernel/entry-common.c:427\n el1h_64_sync+0x64/0x68 arch/arm64/kernel/entry.S:576\n hlist_add_head include/linux/list.h:929 [inline]\n enqueue_timer+0x18/0xa4 kernel/time/timer.c:605\n mod_timer+0x14/0x20 kernel/time/timer.c:1161\n mrp_periodic_timer_arm net/802/mrp.c:614 [inline]\n mrp_periodic_timer+0xa0/0xc0 net/802/mrp.c:627\n call_timer_fn.constprop.0+0x24/0x80 kernel/time/timer.c:1474\n expire_timers+0x98/0xc4 kernel/time/timer.c:1519\n\nTo fix it, we can introduce a new active flags to make sure the timer will\nnot restart." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - The UAF is triggered by locally creating and destroying a VLAN device (rtnetlink/ioctl → register_vlan_dev/unregister_vlan_dev → mrp_init_applicant/mrp_uninit_applicant), not by processing remote or adjacent MRP frames on the mrp_rcv path.\nAC:L - The attacker controls applicant teardown by repeatedly creating and deleting the last VLAN on a device while the join (~200ms) and periodic (1s) timers self-rearm, and can retry until del_timer_sync loses the restart race; this matches attacker-driven timer/teardown races scored AC:L.\nPR:L - VLAN create/delete requires CAP_NET_ADMIN checked with ns_capable/sk_ns_capable against the net's user_ns, which an unprivileged user obtains via user namespaces (e.g. unshare -Urn with veth+vlan), so privileges are Low not High.\nUI:N - The attacker alone creates and destroys VLAN interfaces to drive the race; no separate victim action such as mounting a filesystem or opening a file is required.\nS:U - Impact is a host-kernel heap use-after-free and potential privilege escalation within the same OS security authority, not a VM escape, IOMMU bypass, or other cross-boundary breakout.\nC:H - The freed mrp_applicant (including embedded timer_list and applicant state) is subject to heap reclaim; per UAF guidance this enables arbitrary kernel memory disclosure primitives.\nI:H - KASAN shows a write-after-free in enqueue_timer/mod_timer on the freed applicant, and later timer callbacks continue using the reclaimed object, yielding heap write and control-flow hijack primitives.\nA:H - The confirmed KASAN use-after-free already oopses/crashes the kernel when the rearmed periodic timer runs on freed memory, so availability impact is High." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "include/net/mrp.h", "net/802/mrp.c" ], "versions": [ { "version": "febf018d22347b5df94066bca05d0c11a84e839d", "lessThan": "98f53e591940e4c3818be358c5dc684d5b30cb56", "status": "affected", "versionType": "git" }, { "version": "febf018d22347b5df94066bca05d0c11a84e839d", "lessThan": "aacffc1a8dbf67c5463cb4f67b37143c01ca6fa9", "status": "affected", "versionType": "git" }, { "version": "febf018d22347b5df94066bca05d0c11a84e839d", "lessThan": "78d48bc41f7726113c9f114268d3ab11212814da", "status": "affected", "versionType": "git" }, { "version": "febf018d22347b5df94066bca05d0c11a84e839d", "lessThan": "aadb1507a77b060c529edfeaf67f803e31461f24", "status": "affected", "versionType": "git" }, { "version": "febf018d22347b5df94066bca05d0c11a84e839d", "lessThan": "755eb0879224ffc2a43de724554aeaf0e51e5a64", "status": "affected", "versionType": "git" }, { "version": "febf018d22347b5df94066bca05d0c11a84e839d", "lessThan": "5d5a481a7fd0234f617535dc464ea010804a1129", "status": "affected", "versionType": "git" }, { "version": "febf018d22347b5df94066bca05d0c11a84e839d", "lessThan": "1a185fe83c2a60c1e3596fb9d82dbeb148dc09c6", "status": "affected", "versionType": "git" }, { "version": "febf018d22347b5df94066bca05d0c11a84e839d", "lessThan": "563e45fd5046045cc194af3ba17f5423e1c98170", "status": "affected", "versionType": "git" }, { "version": "febf018d22347b5df94066bca05d0c11a84e839d", "lessThan": "ab0377803dafc58f1e22296708c1c28e309414d6", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "include/net/mrp.h", "net/802/mrp.c" ], "versions": [ { "version": "3.9", "status": "affected" }, { "version": "0", "lessThan": "3.9", "status": "unaffected", "versionType": "semver" }, { "version": "4.9.337", "lessThanOrEqual": "4.9.*", "status": "unaffected", "versionType": "semver" }, { "version": "4.14.303", "lessThanOrEqual": "4.14.*", "status": "unaffected", "versionType": "semver" }, { "version": "4.19.270", "lessThanOrEqual": "4.19.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.4.229", "lessThanOrEqual": "5.4.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.163", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.86", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.0.16", "lessThanOrEqual": "6.0.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.2", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.2", "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": "3.9", "versionEndExcluding": "4.9.337" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.9", "versionEndExcluding": "4.14.303" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.9", "versionEndExcluding": "4.19.270" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.9", "versionEndExcluding": "5.4.229" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.9", "versionEndExcluding": "5.10.163" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.9", "versionEndExcluding": "5.15.86" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.9", "versionEndExcluding": "6.0.16" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.9", "versionEndExcluding": "6.1.2" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.9", "versionEndExcluding": "6.2" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/98f53e591940e4c3818be358c5dc684d5b30cb56" }, { "url": "https://git.kernel.org/stable/c/aacffc1a8dbf67c5463cb4f67b37143c01ca6fa9" }, { "url": "https://git.kernel.org/stable/c/78d48bc41f7726113c9f114268d3ab11212814da" }, { "url": "https://git.kernel.org/stable/c/aadb1507a77b060c529edfeaf67f803e31461f24" }, { "url": "https://git.kernel.org/stable/c/755eb0879224ffc2a43de724554aeaf0e51e5a64" }, { "url": "https://git.kernel.org/stable/c/5d5a481a7fd0234f617535dc464ea010804a1129" }, { "url": "https://git.kernel.org/stable/c/1a185fe83c2a60c1e3596fb9d82dbeb148dc09c6" }, { "url": "https://git.kernel.org/stable/c/563e45fd5046045cc194af3ba17f5423e1c98170" }, { "url": "https://git.kernel.org/stable/c/ab0377803dafc58f1e22296708c1c28e309414d6" } ], "title": "mrp: introduce active flags to prevent UAF when applicant uninit", "x_generator": { "engine": "bippy-1.2.0" } } } }