{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-22999", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-01-13T15:37:45.938Z", "datePublished": "2026-01-25T14:36:13.909Z", "dateUpdated": "2026-08-05T12:20:03.450Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:20:03.450Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: sch_qfq: do not free existing class in qfq_change_class()\n\nFixes qfq_change_class() error case.\n\ncl->qdisc and cl should only be freed if a new class and qdisc\nwere allocated, or we risk various UAF." } ], "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 vulnerable `qfq_change_class()` path is reached through local rtnetlink/tc `RTM_NEWTCLASS` messages, ultimately sent via a netlink socket from userspace. It is not reachable directly from remote network packets.\nAC:L - The attacker controls the qdisc/class setup and can repeatedly attempt the class-change error path; there is no victim race or external timing requirement. Although the observed bad path depends on allocation failure, local memory pressure/failure conditions are attacker-influenceable, and uncertainty is scored upward.\nPR:L - Rtnetlink rejects non-GET tc operations without `CAP_NET_ADMIN` in the relevant network namespace. Because tc/qdisc operations are reachable inside user-created network namespaces on systems allowing unprivileged user namespaces, this is low privilege rather than real init-namespace root.\nUI:N - No victim action is required after the attacker has local execution and sends crafted netlink messages. The trigger is entirely attacker-driven.\nS:U - The impact is within the kernel/local host security authority. This is not a VM escape, IOMMU bypass, or cross-authority boundary violation.\nC:H - The bug frees an existing `struct qfq_class` while it remains reachable from the qdisc class hash and scheduler paths, creating a kernel heap use-after-free. Reclaiming the kmalloc-128 object can turn later class dumps/searches/pointer dereferences into strong information disclosure primitives.\nI:H - The stale class contains pointers such as `qdisc`, `agg`, list/hash nodes, and stats fields that are later read and modified by enqueue/dequeue, graft, dump, reset, and destroy paths. A controllable UAF in these scheduler structures is defensibly exploitable for kernel memory corruption or control-flow/data integrity compromise.\nA:H - The public syzbot report demonstrates a KASAN slab-use-after-free in `qfq_search_class`, and the stale object is also used by multiple qdisc paths. Even without full exploitation, this can cause kernel oops/panic or persistent scheduler corruption." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/sched/sch_qfq.c" ], "versions": [ { "version": "462dbc9101acd38e92eda93c0726857517a24bbd", "lessThan": "2a64fb9b47afffeb5dbab5fd3a518e1436dcc90e", "status": "affected", "versionType": "git" }, { "version": "462dbc9101acd38e92eda93c0726857517a24bbd", "lessThan": "cff6cd703f41d8071995956142729e4bba160363", "status": "affected", "versionType": "git" }, { "version": "462dbc9101acd38e92eda93c0726857517a24bbd", "lessThan": "f06f7635499bc806cbe2bbc8805c7cef8b1edddf", "status": "affected", "versionType": "git" }, { "version": "462dbc9101acd38e92eda93c0726857517a24bbd", "lessThan": "0a234660dc70ce45d771cbc76b20d925b73ec160", "status": "affected", "versionType": "git" }, { "version": "462dbc9101acd38e92eda93c0726857517a24bbd", "lessThan": "362e269bb03f7076ba9990e518aeddb898232e50", "status": "affected", "versionType": "git" }, { "version": "462dbc9101acd38e92eda93c0726857517a24bbd", "lessThan": "e9d8f11652fa08c647bf7bba7dd8163241a332cd", "status": "affected", "versionType": "git" }, { "version": "462dbc9101acd38e92eda93c0726857517a24bbd", "lessThan": "3879cffd9d07aa0377c4b8835c4f64b4fb24ac78", "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/sched/sch_qfq.c" ], "versions": [ { "version": "3.8", "status": "affected" }, { "version": "0", "lessThan": "3.8", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.249", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.199", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.162", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.122", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.67", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.7", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.19", "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": "3.8", "versionEndExcluding": "5.10.249" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.8", "versionEndExcluding": "5.15.199" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.8", "versionEndExcluding": "6.1.162" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.8", "versionEndExcluding": "6.6.122" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.8", "versionEndExcluding": "6.12.67" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.8", "versionEndExcluding": "6.18.7" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.8", "versionEndExcluding": "6.19" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/2a64fb9b47afffeb5dbab5fd3a518e1436dcc90e" }, { "url": "https://git.kernel.org/stable/c/cff6cd703f41d8071995956142729e4bba160363" }, { "url": "https://git.kernel.org/stable/c/f06f7635499bc806cbe2bbc8805c7cef8b1edddf" }, { "url": "https://git.kernel.org/stable/c/0a234660dc70ce45d771cbc76b20d925b73ec160" }, { "url": "https://git.kernel.org/stable/c/362e269bb03f7076ba9990e518aeddb898232e50" }, { "url": "https://git.kernel.org/stable/c/e9d8f11652fa08c647bf7bba7dd8163241a332cd" }, { "url": "https://git.kernel.org/stable/c/3879cffd9d07aa0377c4b8835c4f64b4fb24ac78" } ], "title": "net/sched: sch_qfq: do not free existing class in qfq_change_class()", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "metrics": [ { "other": { "type": "ssvc", "content": { "timestamp": "2026-06-16T20:35:55.025194Z", "id": "CVE-2026-22999", "options": [ { "Exploitation": "none" }, { "Automatable": "no" }, { "Technical Impact": "total" } ], "role": "CISA Coordinator", "version": "2.0.3" } } } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-06-16T20:36:05.459Z" } } ] } }