{"id":"CVE-2026-46259","state":"PUBLISHED","title":"procfs: fix missing RCU protection when reading real_parent in do_task_stat()","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nprocfs: fix missing RCU protection when reading real_parent in do_task_stat()\n\nWhen reading /proc/[pid]/stat, do_task_stat() accesses task->real_parent\nwithout proper RCU protection, which leads to:\n\n  cpu 0                               cpu 1\n  -----                               -----\n  do_task_stat\n    var = task->real_parent\n                                      release_task\n                                        call_rcu(delayed_put_task_struct)\n    task_tgid_nr_ns(var)\n      rcu_read_lock   <--- Too late to protect task->real_parent!\n      task_pid_ptr    <--- UAF!\n      rcu_read_unlock\n\nThis patch uses task_ppid_nr_ns() instead of task_tgid_nr_ns() to add\nproper RCU protection for accessing task->real_parent.","publishedAt":"2026-06-03T15:49:56.428Z","updatedAt":"2026-10-19T19:36:56.158Z","severity":{"score":7.8,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"06fffb1267c9d986687b69d74a46ee332a50575e","status":"affected","lessThan":"fefa0fcd78be465b7ad4c497fa6ec90d64194c04","versionType":"git"},{"version":"06fffb1267c9d986687b69d74a46ee332a50575e","status":"affected","lessThan":"c93a33f28f915d446eea6fb3f0e1def0b3af1982","versionType":"git"},{"version":"06fffb1267c9d986687b69d74a46ee332a50575e","status":"affected","lessThan":"1c8dc5b5517546c68ffae40b948336122bb61306","versionType":"git"},{"version":"06fffb1267c9d986687b69d74a46ee332a50575e","status":"affected","lessThan":"0e64bd46a04a4fd61279aca9f53a664e9e5f7e7e","versionType":"git"},{"version":"06fffb1267c9d986687b69d74a46ee332a50575e","status":"affected","lessThan":"73ec7c96601d61d52310c659145bb06d933a0fa6","versionType":"git"},{"version":"06fffb1267c9d986687b69d74a46ee332a50575e","status":"affected","lessThan":"4f9ae386861e280b7631ca252f798d25575627ee","versionType":"git"},{"version":"06fffb1267c9d986687b69d74a46ee332a50575e","status":"affected","lessThan":"dd8b13cb4ff1a4545a214ed897fdf2bc341155b6","versionType":"git"},{"version":"06fffb1267c9d986687b69d74a46ee332a50575e","status":"affected","lessThan":"76149d53502cf17ef3ae454ff384551236fba867","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/proc/array.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"2.6.26","status":"affected"},{"version":"0","status":"unaffected","lessThan":"2.6.26","versionType":"semver"},{"version":"5.10.252","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.202","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.165","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.128","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.75","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.14","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"6.19.4","status":"unaffected","lessThanOrEqual":"6.19.*","versionType":"semver"},{"version":"7.0","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/proc/array.c"]}],"references":["https://git.kernel.org/stable/c/fefa0fcd78be465b7ad4c497fa6ec90d64194c04","https://git.kernel.org/stable/c/c93a33f28f915d446eea6fb3f0e1def0b3af1982","https://git.kernel.org/stable/c/1c8dc5b5517546c68ffae40b948336122bb61306","https://git.kernel.org/stable/c/0e64bd46a04a4fd61279aca9f53a664e9e5f7e7e","https://git.kernel.org/stable/c/73ec7c96601d61d52310c659145bb06d933a0fa6","https://git.kernel.org/stable/c/4f9ae386861e280b7631ca252f798d25575627ee","https://git.kernel.org/stable/c/dd8b13cb4ff1a4545a214ed897fdf2bc341155b6","https://git.kernel.org/stable/c/76149d53502cf17ef3ae454ff384551236fba867"],"weaknesses":["CWE-416"],"ingestedAt":"2026-10-29T20:12:07.131Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/46xxx/CVE-2026-46259.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-46259","state":"PUBLISHED","datePublished":"2026-06-03T15:49:56.428Z","dateUpdated":"2026-10-19T19:36:56.158Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-05-13T15:03:33.108Z"},"containers":{"cna":{"title":"procfs: fix missing RCU protection when reading real_parent in do_task_stat()","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nprocfs: fix missing RCU protection when reading real_parent in do_task_stat()\n\nWhen reading /proc/[pid]/stat, do_task_stat() accesses task->real_parent\nwithout proper RCU protection, which leads to:\n\n  cpu 0                               cpu 1\n  -----                               -----\n  do_task_stat\n    var = task->real_parent\n                                      release_task\n                                        call_rcu(delayed_put_task_struct)\n    task_tgid_nr_ns(var)\n      rcu_read_lock   <--- Too late to protect task->real_parent!\n      task_pid_ptr    <--- UAF!\n      rcu_read_unlock\n\nThis patch uses task_ppid_nr_ns() instead of task_tgid_nr_ns() to add\nproper RCU protection for accessing task->real_parent."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"06fffb1267c9d986687b69d74a46ee332a50575e","status":"affected","lessThan":"fefa0fcd78be465b7ad4c497fa6ec90d64194c04","versionType":"git"},{"version":"06fffb1267c9d986687b69d74a46ee332a50575e","status":"affected","lessThan":"c93a33f28f915d446eea6fb3f0e1def0b3af1982","versionType":"git"},{"version":"06fffb1267c9d986687b69d74a46ee332a50575e","status":"affected","lessThan":"1c8dc5b5517546c68ffae40b948336122bb61306","versionType":"git"},{"version":"06fffb1267c9d986687b69d74a46ee332a50575e","status":"affected","lessThan":"0e64bd46a04a4fd61279aca9f53a664e9e5f7e7e","versionType":"git"},{"version":"06fffb1267c9d986687b69d74a46ee332a50575e","status":"affected","lessThan":"73ec7c96601d61d52310c659145bb06d933a0fa6","versionType":"git"},{"version":"06fffb1267c9d986687b69d74a46ee332a50575e","status":"affected","lessThan":"4f9ae386861e280b7631ca252f798d25575627ee","versionType":"git"},{"version":"06fffb1267c9d986687b69d74a46ee332a50575e","status":"affected","lessThan":"dd8b13cb4ff1a4545a214ed897fdf2bc341155b6","versionType":"git"},{"version":"06fffb1267c9d986687b69d74a46ee332a50575e","status":"affected","lessThan":"76149d53502cf17ef3ae454ff384551236fba867","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/proc/array.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"2.6.26","status":"affected"},{"version":"0","status":"unaffected","lessThan":"2.6.26","versionType":"semver"},{"version":"5.10.252","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.202","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.165","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.128","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.75","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.14","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"6.19.4","status":"unaffected","lessThanOrEqual":"6.19.*","versionType":"semver"},{"version":"7.0","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/proc/array.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/fefa0fcd78be465b7ad4c497fa6ec90d64194c04"},{"url":"https://git.kernel.org/stable/c/c93a33f28f915d446eea6fb3f0e1def0b3af1982"},{"url":"https://git.kernel.org/stable/c/1c8dc5b5517546c68ffae40b948336122bb61306"},{"url":"https://git.kernel.org/stable/c/0e64bd46a04a4fd61279aca9f53a664e9e5f7e7e"},{"url":"https://git.kernel.org/stable/c/73ec7c96601d61d52310c659145bb06d933a0fa6"},{"url":"https://git.kernel.org/stable/c/4f9ae386861e280b7631ca252f798d25575627ee"},{"url":"https://git.kernel.org/stable/c/dd8b13cb4ff1a4545a214ed897fdf2bc341155b6"},{"url":"https://git.kernel.org/stable/c/76149d53502cf17ef3ae454ff384551236fba867"}],"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 `open()`/`read()` on procfs (`/proc/[pid]/stat` or thread `stat`); there is no network, adjacent-radio, or physical-device path to `do_task_stat()`.\nAC:L - An attacker can reliably race by running concurrent `read()` loops on `/proc/child/stat` while another thread exits and reaps the parent via `wait4()`, controlling both sides of the `release_task()`/`call_rcu()` window.\nPR:L - Triggering the bug needs only an unprivileged local account that can read procfs (default `hidepid=off` allows reading other users’ `stat`); no real root or init-namespace-only capability is required.\nUI:N - Exploitation is fully attacker-driven through syscalls and process lifecycle control; no victim user action (clicks, mounts, etc.) is needed.\nS:U - Impact is confined to kernel memory corruption and privilege escalation within the same kernel security domain, not a cross-boundary escape such as VM guest-to-host.\nC:H - The UAF dereferences freed `task_struct` memory via `task_pid_ptr()`/`__task_pid_nr_ns()`, enabling disclosure of stale slab contents and kernel pointers that can be groomed into an arbitrary-read primitive.\nI:H - Use-after-free on a `task_struct` slab object can be leveraged with heap grooming for control of freed memory and potential arbitrary write or code execution, not merely a bounded or cosmetic change.\nA:H - Concurrent UAF access to a freed parent `task_struct` can cause kernel oops/panic (KASAN reports slab-use-after-free class failures) even when full exploitation is not attempted."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-05T12:30:48.120Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.26","versionEndExcluding":"5.10.252"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.26","versionEndExcluding":"5.15.202"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.26","versionEndExcluding":"6.1.165"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.26","versionEndExcluding":"6.6.128"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.26","versionEndExcluding":"6.12.75"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.26","versionEndExcluding":"6.18.14"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.26","versionEndExcluding":"6.19.4"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.26","versionEndExcluding":"7.0"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2026-46259","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"version":"2.0.3","timestamp":"2026-10-16T15:21:25.410048Z"}}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-416","lang":"en","type":"CWE","description":"CWE-416 Use After Free"}]}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-19T19:36:56.158Z"}}]}}}