CVE-2026-90325

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-90325", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-11T19:38:34.802Z", "datePublished": "2026-09-17T16:08:40.710Z", "dateUpdated": "2026-10-19T09:01:42.317Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-19T09:01:42.317Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nblk-cgroup: skip dying blkg in blkcg_activate_policy()\n\nWhen switching IO schedulers on a block device, blkcg_activate_policy()\ncan race with concurrent blkcg deletion, leading to a use-after-free in\nrcu_accelerate_cbs.\n\nT1: T2:\n blkg_destroy\n kill(&blkg->refcnt) // blkg->refcnt=1->0\n blkg_release // call_rcu(__blkg_release)\n ...\n blkg_free_workfn\n ->pd_free_fn(pd)\nelv_iosched_store\nelevator_switch\n...\niterate blkg list\nblkg_get(blkg) // blkg->refcnt=0->1\n list_del_init(&blkg->q_node)\nblkg_put(pinned_blkg) // blkg->refcnt=1->0\nblkg_release // call_rcu again\nrcu_accelerate_cbs // uaf\n\nFix this by checking hlist_unhashed(&blkg->blkcg_node) before getting\na reference to the blkg. This is the same check used in blkg_destroy()\nto detect if a blkg has already been destroyed. If the blkg is already\nunhashed, skip processing it since it's being destroyed."}], "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 reached by writing the local sysfs file /sys/block/<dev>/queue/scheduler (elv_iosched_store \u2192 elevator_switch \u2192 bfq_create_group_hierarchy \u2192 blkcg_activate_policy) or by writing the local cgroup files io.max (tg_set_limit \u2192 blk_throtl_init) or io.latency (iolatency_set_limit \u2192 blk_iolatency_init). No remote protocol carries the triggering state.\nAC:L - The attacker drives both sides: one thread writes io.max/io.latency or queue/scheduler so blkcg_activate_policy() takes the GFP_NOWAIT-fail retry and calls blkg_get() on a q->blkg_list entry, while another rmdirs a sibling io cgroup so blkcg_css_offline() \u2192 blkg_destroy() kills that blkg's percpu_ref. The mkdir/write/rmdir cycle can be repeated until the window hits.\nPR:L - cgroup_add_file() creates io.max and io.latency with mode 0644 and current_fsuid(), so an unprivileged user who mkdir's in a delegated cgroup v2 subtree (systemd user@.service, rootless containers) can write those files and rmdir the cgroup. tg_set_limit()/iolatency_set_limit() have no capability check, and blkg_conf_open_bdev() looks up the disk by MAJ:MIN via blkdev_get_no_open() without opening it.\nUI:N - The attacker performs the mkdir, the io.max/io.latency or scheduler write that enters blkcg_activate_policy(), and the concurrent rmdir that runs blkg_destroy(), all from its own processes; no other user must mount a device or open a file.\nS:U - Double call_rcu on blkg->rcu_head corrupts host-kernel RCU callback lists and the slab-backed blkcg_gq. That stays inside the same kernel security authority and is not a VM, IOMMU, or hypervisor escape.\nC:H - blkcg_activate_policy() calls blkg_get() (percpu_ref_get, not tryget) on a blkg whose refcnt blkg_destroy() already killed, resurrecting it; the matching blkg_put() after mutex_unlock races blkg_free_workfn()'s kfree(blkg) and issues a second call_rcu on the same rcu_head, which the report shows as a UAF in rcu_accelerate_cbs. A UAF on the RCU list and blkcg_gq is an arbitrary kernel-memory read.\nI:H - The second call_rcu(&blkg->rcu_head) from the resurrected blkg_put() corrupts the RCU callback list (rcu_accelerate_cbs) while blkg_free_workfn() still does list_del_init() and pd_free_fn() on that object. Those writes through a freed, sprayable blkcg_gq are a kernel write primitive suitable for control-flow hijack.\nA:H - The commit documents a use-after-free in rcu_accelerate_cbs from the second call_rcu on blkg->rcu_head after blkg_get() resurrects a killed ref; that UAF oopses or panics the kernel even if it is not further exploited."}]}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["block/blk-cgroup.c"], "versions": [{"version": "81c1188905f88b77743d1fdeeedfc8cb7b67787d", "lessThan": "b5dae1cd0d8368b4338430ff93403df67f0b8bcc", "status": "affected", "versionType": "git"}, {"version": "bfe46d2efe46c5c952f982e2ca94fe2ec5e58e2a", "lessThan": "083b58373463a6e5ee60ecb135269348f68ad7df", "status": "affected", "versionType": "git"}, {"version": "f1c006f1c6850c14040f8337753a63119bba39b9", "lessThan": "1a267295b1ea6a6477963f3fda84adfecd48fcad", "status": "affected", "versionType": "git"}, {"version": "f1c006f1c6850c14040f8337753a63119bba39b9", "lessThan": "7337d012ca3fc3a6a2d1c8e2a19c6d97c38b410d", "status": "affected", "versionType": "git"}, {"version": "f1c006f1c6850c14040f8337753a63119bba39b9", "lessThan": "3d8c3da95c75a4d312e272fc7b4076dd3ba9115c", "status": "affected", "versionType": "git"}, {"version": "f1c006f1c6850c14040f8337753a63119bba39b9", "lessThan": "d8c872901e6459339374e9eea80aa919176c2ccd", "status": "affected", "versionType": "git"}, {"version": "f1c006f1c6850c14040f8337753a63119bba39b9", "lessThan": "5e9220389920f33b6a804d50c548cd0cd1b04634", "status": "affected", "versionType": "git"}, {"version": "6.1.16", "lessThan": "6.1.17", "status": "affected", "versionType": "semver"}, {"version": "6.2.3", "lessThan": "6.2.4", "status": "affected", "versionType": "semver"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["block/blk-cgroup.c"], "versions": [{"version": "6.3", "status": "affected"}, {"version": "0", "lessThan": "6.3", "status": "unaffected", "versionType": "semver"}, {"version": "6.1.17", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.2.4", "lessThanOrEqual": "6.2.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.6.157", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.12.110", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.52", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.2.6", "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": "6.1.16", "versionEndExcluding": "6.1.17"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.2.3", "versionEndExcluding": "6.2.4"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.3", "versionEndExcluding": "6.6.157"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.3", "versionEndExcluding": "6.12.110"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.3", "versionEndExcluding": "6.18.52"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.3", "versionEndExcluding": "7.2.6"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.3", "versionEndExcluding": "7.3"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/b5dae1cd0d8368b4338430ff93403df67f0b8bcc"}, {"url": "https://git.kernel.org/stable/c/083b58373463a6e5ee60ecb135269348f68ad7df"}, {"url": "https://git.kernel.org/stable/c/1a267295b1ea6a6477963f3fda84adfecd48fcad"}, {"url": "https://git.kernel.org/stable/c/7337d012ca3fc3a6a2d1c8e2a19c6d97c38b410d"}, {"url": "https://git.kernel.org/stable/c/3d8c3da95c75a4d312e272fc7b4076dd3ba9115c"}, {"url": "https://git.kernel.org/stable/c/d8c872901e6459339374e9eea80aa919176c2ccd"}, {"url": "https://git.kernel.org/stable/c/5e9220389920f33b6a804d50c548cd0cd1b04634"}], "title": "blk-cgroup: skip dying blkg in blkcg_activate_policy()", "x_generator": {"engine": "bippy-1.2.0"}}}}

{}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["block/blk-cgroup.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "b5dae1cd0d8368b4338430ff93403df67f0b8bcc", "status": "affected", "version": "81c1188905f88b77743d1fdeeedfc8cb7b67787d", "versionType": "git"}, {"lessThan": "083b58373463a6e5ee60ecb135269348f68ad7df", "status": "affected", "version": "bfe46d2efe46c5c952f982e2ca94fe2ec5e58e2a", "versionType": "git"}, {"lessThan": "1a267295b1ea6a6477963f3fda84adfecd48fcad", "status": "affected", "version": "f1c006f1c6850c14040f8337753a63119bba39b9", "versionType": "git"}, {"lessThan": "7337d012ca3fc3a6a2d1c8e2a19c6d97c38b410d", "status": "affected", "version": "f1c006f1c6850c14040f8337753a63119bba39b9", "versionType": "git"}, {"lessThan": "3d8c3da95c75a4d312e272fc7b4076dd3ba9115c", "status": "affected", "version": "f1c006f1c6850c14040f8337753a63119bba39b9", "versionType": "git"}, {"lessThan": "d8c872901e6459339374e9eea80aa919176c2ccd", "status": "affected", "version": "f1c006f1c6850c14040f8337753a63119bba39b9", "versionType": "git"}, {"lessThan": "5e9220389920f33b6a804d50c548cd0cd1b04634", "status": "affected", "version": "f1c006f1c6850c14040f8337753a63119bba39b9", "versionType": "git"}, {"lessThan": "6.1.17", "status": "affected", "version": "6.1.16", "versionType": "semver"}, {"lessThan": "6.2.4", "status": "affected", "version": "6.2.3", "versionType": "semver"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["block/blk-cgroup.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "6.3"}, {"lessThan": "6.3", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "6.1.*", "status": "unaffected", "version": "6.1.17", "versionType": "semver"}, {"lessThanOrEqual": "6.2.*", "status": "unaffected", "version": "6.2.4", "versionType": "semver"}, {"lessThanOrEqual": "6.6.*", "status": "unaffected", "version": "6.6.157", "versionType": "semver"}, {"lessThanOrEqual": "6.12.*", "status": "unaffected", "version": "6.12.110", "versionType": "semver"}, {"lessThanOrEqual": "6.18.*", "status": "unaffected", "version": "6.18.52", "versionType": "semver"}, {"lessThanOrEqual": "7.2.*", "status": "unaffected", "version": "7.2.6", "versionType": "semver"}, {"lessThanOrEqual": "*", "status": "unaffected", "version": "7.3", "versionType": "original_commit_for_fix"}]}], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nblk-cgroup: skip dying blkg in blkcg_activate_policy()\n\nWhen switching IO schedulers on a block device, blkcg_activate_policy()\ncan race with concurrent blkcg deletion, leading to a use-after-free in\nrcu_accelerate_cbs.\n\nT1: T2:\n blkg_destroy\n kill(&blkg->refcnt) // blkg->refcnt=1->0\n blkg_release // call_rcu(__blkg_release)\n ...\n blkg_free_workfn\n ->pd_free_fn(pd)\nelv_iosched_store\nelevator_switch\n...\niterate blkg list\nblkg_get(blkg) // blkg->refcnt=0->1\n list_del_init(&blkg->q_node)\nblkg_put(pinned_blkg) // blkg->refcnt=1->0\nblkg_release // call_rcu again\nrcu_accelerate_cbs // uaf\n\nFix this by checking hlist_unhashed(&blkg->blkcg_node) before getting\na reference to the blkg. This is the same check used in blkg_destroy()\nto detect if a blkg has already been destroyed. If the blkg is already\nunhashed, skip processing it since it's being destroyed."}], "id": "CVE-2026-90325", "lastModified": "2026-10-19T09:19:26.523", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "LOCAL", "availabilityImpact": "HIGH", "baseScore": 7.8, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 1.8, "impactScore": 5.9, "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary"}]}, "published": "2026-09-17T17:17:30.540", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/083b58373463a6e5ee60ecb135269348f68ad7df"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/1a267295b1ea6a6477963f3fda84adfecd48fcad"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/3d8c3da95c75a4d312e272fc7b4076dd3ba9115c"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/5e9220389920f33b6a804d50c548cd0cd1b04634"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/7337d012ca3fc3a6a2d1c8e2a19c6d97c38b410d"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/b5dae1cd0d8368b4338430ff93403df67f0b8bcc"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/d8c872901e6459339374e9eea80aa919176c2ccd"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

{}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[81c1188905f88b77743d1fdeeedfc8cb7b67787d,b5dae1cd0d8368b4338430ff93403df67f0b8bcc)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[bfe46d2efe46c5c952f982e2ca94fe2ec5e58e2a,083b58373463a6e5ee60ecb135269348f68ad7df)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[f1c006f1c6850c14040f8337753a63119bba39b9,1a267295b1ea6a6477963f3fda84adfecd48fcad)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[f1c006f1c6850c14040f8337753a63119bba39b9,7337d012ca3fc3a6a2d1c8e2a19c6d97c38b410d)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[f1c006f1c6850c14040f8337753a63119bba39b9,3d8c3da95c75a4d312e272fc7b4076dd3ba9115c)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[f1c006f1c6850c14040f8337753a63119bba39b9,d8c872901e6459339374e9eea80aa919176c2ccd)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[f1c006f1c6850c14040f8337753a63119bba39b9,5e9220389920f33b6a804d50c548cd0cd1b04634)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[6.1.16,6.1.17)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[6.2.3,6.2.4)"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}, {"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "6.3"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[0,6.3)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.1.17,6.2.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.2.4,6.3.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.6.157,6.7.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.12.110,6.13.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.18.52,6.19.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[7.2.6,7.3.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[7.3-rc1,*]"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}], "created": "2026-09-19T08:30:16.782570+00:00", "updated": "2026-09-20T00:30:16.214442+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel"], "weaknesses": ["CWE-416"]}