{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-72427", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-08-09T03:40:39.928Z", "datePublished": "2026-08-15T05:56:44.197Z", "dateUpdated": "2026-08-17T05:44:07.623Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-17T05:44:07.623Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fix effective prog array index with BPF_F_PREORDER\n\nreplace_effective_prog() and purge_effective_progs() located the slot in\nthe effective array by walking the program hlist and counting entries\nlinearly. That count does not match the array layout: compute_effective_\nprogs() places BPF_F_PREORDER programs at the front (ancestor cgroup\nfirst, attach order within a cgroup) and the rest after them (descendant\ncgroup first). So when a preorder program is present, the linear hlist\nposition no longer equals the program's index in the effective array.\n\nFor replace_effective_prog() (bpf_link_update()) this overwrote the\nwrong slot, corrupting the effective order. For purge_effective_progs(),\nit could dummy out a slot belonging to a different program and leave the\ndetached program in the array while bpf_prog_put() drops its reference,\ni.e. a use-after-free.\n\nFix both by replaying compute_effective_progs()'s placement (including\nthe per-cgroup preorder reversal) in a shared effective_prog_pos()\nhelper. Identify the entry by its struct bpf_prog_list pointer rather\nthan by (prog, link) value, so the lookup resolves to exactly the\nattachment the syscall selected even when the same bpf_prog is attached\nto several cgroups in the hierarchy." } ], "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 - Exploitation requires local bpf() syscalls (BPF_LINK_CREATE/BPF_PROG_ATTACH with BPF_F_PREORDER, BPF_LINK_UPDATE, BPF_PROG_DETACH/BPF_LINK_DETACH) through __cgroup_bpf_replace/__cgroup_bpf_detach in kernel/bpf/cgroup.c; per kernel CNA guidance BPF cgroup hooks are Local even when later triggered by packets.\nAC:L - Attacker fully controls cgroup hierarchy, BPF_F_PREORDER|BPF_F_ALLOW_MULTI attachments, and bpf_link_update/detach timing; purge_effective_progs UAF needs update_effective_progs() OOM which attacker can induce via memory pressure/large hierarchies, and bpf_link_update ordering corruption triggers without OOM.\nPR:L - Reaching the bug requires CAP_BPF (and CAP_NET_ADMIN for most cgroup BPF types) plus cgroup v2 attach access, commonly obtainable by unprivileged users via delegated cgroups or user namespaces (CAP_BPF/CAP_NET_ADMIN), not init-namespace root.\nUI:N - Attacker loads, attaches, and updates/detaches their own cgroup BPF programs and links via bpf(); no separate victim or administrator action is required.\nS:U - The bug corrupts kernel cgroup BPF effective-prog arrays causing UAF/ordering corruption within the same kernel security domain, enabling local privilege escalation rather than crossing VM, IOMMU, or sandbox boundaries.\nC:H - purge_effective_progs() can leave a detached bpf_prog pointer in the RCU-protected effective array while bpf_prog_put() frees it, yielding a use-after-free read when __cgroup_bpf_run_filter_* later executes the stale program under RCU.\nI:H - UAF of bpf_prog objects enables heap reuse for arbitrary kernel writes/control-flow hijack; bpf_link_update() mis-indexing can overwrite another attachment's effective slot so attacker-controlled BPF runs in place of security/filter programs on traffic for the whole cgroup tree.\nA:H - Freed-but-still-referenced programs are executed from softirq/network cgroup hooks and reliably cause kernel oops/panic/KASAN failures; ordering corruption can also crash or hang filtering paths serving container/cloud workloads." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "kernel/bpf/cgroup.c" ], "versions": [ { "version": "bc8023ef3b11410682e5d4990e05e5bc2d3e1c94", "lessThan": "525e408c27ae714e538b8c608c3a974df3ab6c92", "status": "affected", "versionType": "git" }, { "version": "555c0b713ca83968d3c843cb15485b9ba3367b1b", "lessThan": "41b4320b84fdafe1ab586b06453d30d50415db59", "status": "affected", "versionType": "git" }, { "version": "4b82b181a26cff8bf7adc3a85a88d121d92edeaf", "lessThan": "9697db03e010391c55ae75192cbdf30c5a72c114", "status": "affected", "versionType": "git" }, { "version": "4b82b181a26cff8bf7adc3a85a88d121d92edeaf", "lessThan": "b584f107ab90222bd825dcb4c5977326ff684109", "status": "affected", "versionType": "git" }, { "version": "4b82b181a26cff8bf7adc3a85a88d121d92edeaf", "lessThan": "f08aaee3152d0dfc578b3f2586932d82062701dd", "status": "affected", "versionType": "git" }, { "version": "4707ad649cf662add3058bff47430817811b048d", "status": "affected", "versionType": "git" }, { "version": "6.6.93", "lessThan": "6.6.145", "status": "affected", "versionType": "semver" }, { "version": "6.12.31", "lessThan": "6.12.97", "status": "affected", "versionType": "semver" }, { "version": "6.14.9", "lessThan": "6.15", "status": "affected", "versionType": "semver" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "kernel/bpf/cgroup.c" ], "versions": [ { "version": "6.15", "status": "affected" }, { "version": "0", "lessThan": "6.15", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.145", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.97", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.40", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.1.5", "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": "6.6.93", "versionEndExcluding": "6.6.145" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.12.31", "versionEndExcluding": "6.12.97" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.15", "versionEndExcluding": "6.18.40" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.15", "versionEndExcluding": "7.1.5" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.15", "versionEndExcluding": "7.2" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.14.9" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/525e408c27ae714e538b8c608c3a974df3ab6c92" }, { "url": "https://git.kernel.org/stable/c/41b4320b84fdafe1ab586b06453d30d50415db59" }, { "url": "https://git.kernel.org/stable/c/9697db03e010391c55ae75192cbdf30c5a72c114" }, { "url": "https://git.kernel.org/stable/c/b584f107ab90222bd825dcb4c5977326ff684109" }, { "url": "https://git.kernel.org/stable/c/f08aaee3152d0dfc578b3f2586932d82062701dd" } ], "title": "bpf: Fix effective prog array index with BPF_F_PREORDER", "x_generator": { "engine": "bippy-1.2.0" } } } }