{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2024-56672", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2024-12-27T15:00:39.845Z", "datePublished": "2024-12-27T15:06:33.358Z", "dateUpdated": "2026-08-05T11:46:00.581Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T11:46:00.581Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nblk-cgroup: Fix UAF in blkcg_unpin_online()\n\nblkcg_unpin_online() walks up the blkcg hierarchy putting the online pin. To\nwalk up, it uses blkcg_parent(blkcg) but it was calling that after\nblkcg_destroy_blkgs(blkcg) which could free the blkcg, leading to the\nfollowing UAF:\n\n ==================================================================\n BUG: KASAN: slab-use-after-free in blkcg_unpin_online+0x15a/0x270\n Read of size 8 at addr ffff8881057678c0 by task kworker/9:1/117\n\n CPU: 9 UID: 0 PID: 117 Comm: kworker/9:1 Not tainted 6.13.0-rc1-work-00182-gb8f52214c61a-dirty #48\n Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS unknown 02/02/2022\n Workqueue: cgwb_release cgwb_release_workfn\n Call Trace:\n \n dump_stack_lvl+0x27/0x80\n print_report+0x151/0x710\n kasan_report+0xc0/0x100\n blkcg_unpin_online+0x15a/0x270\n cgwb_release_workfn+0x194/0x480\n process_scheduled_works+0x71b/0xe20\n worker_thread+0x82a/0xbd0\n kthread+0x242/0x2c0\n ret_from_fork+0x33/0x70\n ret_from_fork_asm+0x1a/0x30\n \n ...\n Freed by task 1944:\n kasan_save_track+0x2b/0x70\n kasan_save_free_info+0x3c/0x50\n __kasan_slab_free+0x33/0x50\n kfree+0x10c/0x330\n css_free_rwork_fn+0xe6/0xb30\n process_scheduled_works+0x71b/0xe20\n worker_thread+0x82a/0xbd0\n kthread+0x242/0x2c0\n ret_from_fork+0x33/0x70\n ret_from_fork_asm+0x1a/0x30\n\nNote that the UAF is not easy to trigger as the free path is indirected\nbehind a couple RCU grace periods and a work item execution. I could only\ntrigger it with artifical msleep() injected in blkcg_unpin_online().\n\nFix it by reading the parent pointer before destroying the blkcg's blkg's." } ], "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 bug is reached only through local operations — creating/enabling an `io` cgroup, dirtying pages to instantiate a cgroup writeback structure, and rmdir'ing the cgroup. No network-facing code path reaches `blkcg_unpin_online()`.\nAC:L - The attacker drives both sides: the cgwb release that reaches the stale read and the css free chain are both initiated by its own cgroup teardown, and the window is widened at will via `blkcg_destroy_blkgs()`'s `cond_resched()` loop (blkg count, CPU load) while the create/write/rmdir cycle can be repeated indefinitely until the race lands.\nPR:L - An unprivileged user needs only write access to a delegated cgroup v2 subtree with the io controller enabled — standard under systemd user delegation, container runtimes, and unprivileged podman — plus ordinary buffered writes; no capability check guards the path.\nUI:N - The attacker performs every step itself — cgroup creation, file writes, and cgroup removal — with no victim action required.\nS:U - The corruption occurs in kernel slab memory and impacts the same kernel security authority; no VM, IOMMU, or hypervisor boundary is crossed.\nC:H - `struct blkcg` is allocated from a general kmalloc cache, so the freed object can be sprayed with attacker-controlled data; the stale `css.parent` read produces a controlled pointer that is subsequently dereferenced, giving a path to disclose arbitrary kernel memory.\nI:H - The UAF-derived pointer is fed straight into `refcount_dec_and_test(&blkcg->online_pin)` — an arbitrary decrement — and into `blkcg_destroy_blkgs()`, which performs hlist unlink writes on the bogus object, yielding write primitives suitable for control-flow hijack and privilege escalation.\nA:H - Even unweaponized, the slab-use-after-free reliably corrupts memory and oopses/panics the kernel, as demonstrated by the reported KASAN splat in a cgwb_release kworker." } ] } ], "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": "4308a434e5e08c78676aa66bc626ef78cbef0883", "lessThan": "83f5a87ee8caa76a917f59912a74d6811f773c67", "status": "affected", "versionType": "git" }, { "version": "4308a434e5e08c78676aa66bc626ef78cbef0883", "lessThan": "8a07350fe070017a887433f4d6909433955be5f1", "status": "affected", "versionType": "git" }, { "version": "4308a434e5e08c78676aa66bc626ef78cbef0883", "lessThan": "64afc6fe24c9896c0153e5a199bcea241ecb0d5c", "status": "affected", "versionType": "git" }, { "version": "4308a434e5e08c78676aa66bc626ef78cbef0883", "lessThan": "5baa28569c924d9a90d036c2aaab79f791fedaf8", "status": "affected", "versionType": "git" }, { "version": "4308a434e5e08c78676aa66bc626ef78cbef0883", "lessThan": "29d1e06560f0f6179062ac638b4064deb637d1ad", "status": "affected", "versionType": "git" }, { "version": "4308a434e5e08c78676aa66bc626ef78cbef0883", "lessThan": "86e6ca55b83c575ab0f2e105cf08f98e58d3d7af", "status": "affected", "versionType": "git" } ] }, { "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": "5.7", "status": "affected" }, { "version": "0", "lessThan": "5.7", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.234", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.177", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.121", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.67", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.6", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.13", "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": "5.7", "versionEndExcluding": "5.10.234" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.7", "versionEndExcluding": "5.15.177" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.7", "versionEndExcluding": "6.1.121" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.7", "versionEndExcluding": "6.6.67" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.7", "versionEndExcluding": "6.12.6" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.7", "versionEndExcluding": "6.13" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/83f5a87ee8caa76a917f59912a74d6811f773c67" }, { "url": "https://git.kernel.org/stable/c/8a07350fe070017a887433f4d6909433955be5f1" }, { "url": "https://git.kernel.org/stable/c/64afc6fe24c9896c0153e5a199bcea241ecb0d5c" }, { "url": "https://git.kernel.org/stable/c/5baa28569c924d9a90d036c2aaab79f791fedaf8" }, { "url": "https://git.kernel.org/stable/c/29d1e06560f0f6179062ac638b4064deb637d1ad" }, { "url": "https://git.kernel.org/stable/c/86e6ca55b83c575ab0f2e105cf08f98e58d3d7af" } ], "title": "blk-cgroup: Fix UAF in blkcg_unpin_online()", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "metrics": [ { "cvssV3_1": { "scope": "UNCHANGED", "version": "3.1", "baseScore": 7.8, "attackVector": "LOCAL", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "integrityImpact": "HIGH", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "LOW", "confidentialityImpact": "HIGH" } }, { "other": { "type": "ssvc", "content": { "id": "CVE-2024-56672", "role": "CISA Coordinator", "options": [ { "Exploitation": "none" }, { "Automatable": "no" }, { "Technical Impact": "total" } ], "version": "2.0.3", "timestamp": "2025-02-10T17:12:31.915249Z" } } } ], "problemTypes": [ { "descriptions": [ { "lang": "en", "type": "CWE", "cweId": "CWE-416", "description": "CWE-416 Use After Free" } ] } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2025-02-10T17:21:07.331Z" } }, { "title": "CVE Program Container", "references": [ { "url": "https://lists.debian.org/debian-lts-announce/2025/03/msg00001.html" }, { "url": "https://lists.debian.org/debian-lts-announce/2025/03/msg00002.html" } ], "providerMetadata": { "orgId": "af854a3a-2127-422b-91ae-364da2661108", "shortName": "CVE", "dateUpdated": "2025-11-03T20:52:20.150Z" } }, { "x_adpType": "supplier", "providerMetadata": { "orgId": "0b142b55-0307-4c5a-b3c9-f314f3fb7c5e", "shortName": "siemens-SADP", "dateUpdated": "2026-05-12T12:01:24.932Z" }, "affected": [ { "vendor": "Siemens", "product": "SIMATIC S7-1500 TM MFP - GNU/Linux subsystem", "versions": [ { "status": "affected", "version": "0", "lessThan": "*", "versionType": "custom" } ], "defaultStatus": "unknown" } ], "references": [ { "url": "https://cert-portal.siemens.com/productcert/html/ssa-265688.html" } ] } ] } }