{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-80929", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-08-26T14:34:25.802Z", "datePublished": "2026-09-11T19:42:04.778Z", "dateUpdated": "2026-10-19T08:45:13.127Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-19T08:45:13.127Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsysctl: move the \"cad_pid\" entry from pid_table[] to kern_reboot_table[]\n\ncad_pid is global, and kill_cad_pid() is only used in the root namespace.\n\nHowever, due to pid_table_root_permissions(), a non-root user can unshare\npid/user namespaces and modify it from the child namespace. This makes no\nsense and is simply wrong.\n\nMove it to kern_reboot_table[] where it logically belongs; this ensures\nthat only GLOBAL_ROOT_UID can read/modify this sysctl.\n\nNote that this patch doesn't preserve \"#ifdef CONFIG_PROC_SYSCTL\" around\nthe \"cad_pid\"; CONFIG_PROC_SYSCTL selects CONFIG_SYSCTL, so it is always\nset when kern_reboot_table[] is compiled." } ], "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 - Unprivileged local processes reach proc_do_cad_pid() by opening and writing /proc/sys/kernel/cad_pid after creating user and PID namespaces; this is a procfs sysctl syscall path, not a network, adjacent-wireless, or physical-device handler.\nAC:L - The attacker fully controls namespace creation and concurrent sysctl reads/writes of the shared global cad_pid pointer, so the proc_do_cad_pid() use-after-free race does not depend on victim state, rare configs, or other conditions outside attacker influence.\nPR:L - pid_table_root_permissions() treats CAP_SYS_ADMIN or uid 0 in the PID namespace's user namespace as owner of the 0600 cad_pid sysctl, which an unprivileged user obtains by unsharing user and PID namespaces rather than needing init-namespace root.\nUI:N - The attacker triggers the flaw entirely through their own unshare, proc mount, and read/write of kernel.cad_pid; no other user must press Ctrl-Alt-Del, mount a filesystem, or take any action.\nS:U - Successful exploitation corrupts host kernel memory and hijacks the global cad_pid used by kill_cad_pid(); this remains inside the kernel's security authority and is not a VM, IOMMU, or DMA boundary bypass.\nC:H - Racing a cad_pid sysctl write (put_pid of the last reference) against a sysctl read use-after-frees struct pid in pid_vnr()/pid_nr_ns(), which per kernel CVSS guidance provides an arbitrary kernel-read primitive via slab reuse.\nI:H - The same use-after-free of struct pid is exploitable for heap spraying and control-flow hijack of kernel PID/signal paths, and the write also replaces host-global cad_pid so privileged kernel SIGINT/SIGPWR are redirected away from init.\nA:H - The use-after-free produces a kernel oops or panic on the pid_nr_ns() dereference of freed memory, as shown by the KASAN report; replacing cad_pid also persistently breaks host Ctrl-Alt-Del and power-button delivery to init." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "kernel/pid.c", "kernel/reboot.c" ], "versions": [ { "version": "e054bcbe7e7af2baad3752f1a4916a7fffc0457e", "lessThan": "e8527de7fea191fda704792a56081f9009aeec37", "status": "affected", "versionType": "git" }, { "version": "e054bcbe7e7af2baad3752f1a4916a7fffc0457e", "lessThan": "a09bc4eaa67e1a72df3b6d0beb3afeef1e1fdfcd", "status": "affected", "versionType": "git" }, { "version": "e054bcbe7e7af2baad3752f1a4916a7fffc0457e", "lessThan": "7170ca01623b399c97f2ae9d3e228badc1f25ea3", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "kernel/pid.c", "kernel/reboot.c" ], "versions": [ { "version": "6.17", "status": "affected" }, { "version": "0", "lessThan": "6.17", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.50", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2.4", "lessThanOrEqual": "7.2.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.3", "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": "6.17", "versionEndExcluding": "6.18.50" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.17", "versionEndExcluding": "7.2.4" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.17", "versionEndExcluding": "7.3" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/e8527de7fea191fda704792a56081f9009aeec37" }, { "url": "https://git.kernel.org/stable/c/a09bc4eaa67e1a72df3b6d0beb3afeef1e1fdfcd" }, { "url": "https://git.kernel.org/stable/c/7170ca01623b399c97f2ae9d3e228badc1f25ea3" } ], "title": "sysctl: move the \"cad_pid\" entry from pid_table[] to kern_reboot_table[]", "x_generator": { "engine": "bippy-1.2.0" } } } }