{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2024-35860", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2024-05-17T13:50:33.107Z", "datePublished": "2024-05-19T08:34:19.368Z", "dateUpdated": "2026-08-05T11:30:24.039Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T11:30:24.039Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: support deferring bpf_link dealloc to after RCU grace period\n\nBPF link for some program types is passed as a \"context\" which can be\nused by those BPF programs to look up additional information. E.g., for\nmulti-kprobes and multi-uprobes, link is used to fetch BPF cookie values.\n\nBecause of this runtime dependency, when bpf_link refcnt drops to zero\nthere could still be active BPF programs running accessing link data.\n\nThis patch adds generic support to defer bpf_link dealloc callback to\nafter RCU GP, if requested. This is done by exposing two different\ndeallocation callbacks, one synchronous and one deferred. If deferred\none is provided, bpf_link_free() will schedule dealloc_deferred()\ncallback to happen after RCU GP.\n\nBPF is using two flavors of RCU: \"classic\" non-sleepable one and RCU\ntasks trace one. The latter is used when sleepable BPF programs are\nused. bpf_link_free() accommodates that by checking underlying BPF\nprogram's sleepable flag, and goes either through normal RCU GP only for\nnon-sleepable, or through RCU tasks trace GP *and* then normal RCU GP\n(taking into account rcu_trace_implies_rcu_gp() optimization), if BPF\nprogram is sleepable.\n\nWe use this for multi-kprobe and multi-uprobe links, which dereference\nlink during program run. We also preventively switch raw_tp link to use\ndeferred dealloc callback, as upcoming changes in bpf-next tree expose\nraw_tp link data (specifically, cookie value) to BPF program at runtime\nas well." } ], "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 vulnerability is reached solely through the local `bpf()` syscall — `BPF_PROG_LOAD` plus `BPF_LINK_CREATE` for a kprobe_multi/uprobe_multi link, then closing the link fd while the probes fire. No network or remote-peer input is involved anywhere on the path.\nAC:L - The attacker controls both sides of the race: it picks which kernel/user functions are probed (including ones that block, so return-hooks fire arbitrarily late), drives them in a loop across all CPUs, and closes the link fd at will; three independent syzbot reproducers hit it in practice, so no condition outside attacker influence is required.\nPR:L - Creating these links needs CAP_BPF+CAP_PERFMON, which `bpf_token_capable()` grants at `ns_capable()` level to a delegated BPF token inside a container, and which ordinary non-root tracing/observability service accounts routinely hold — that is a low-privileged account, not administrative control of the host.\nUI:N - The whole sequence — load program, create link, trigger the probes, close the fd — happens inside the attacker's own process. No action by any other user or administrator is needed.\nS:U - The use-after-free and everything it corrupts stay inside the kernel's own memory and privilege domain; no hypervisor, IOMMU, or other security-authority boundary is crossed.\nC:H - `bpf_kprobe_multi_cookie()` bsearches the freed `addrs` array and returns `*cookie` from the freed `cookies` allocation directly to the running BPF program, which can exfiltrate it via a map — a read primitive over attacker-sprayed reclaimed slab, and the freed link is fully groomable.\nI:H - `kprobe_multi_link_prog_run()`/`uprobe_prog_run()` load `link->link.prog` out of freed memory and then indirect-call through it via `bpf_prog_run()`, and `fprobe_exit_handler()` calls `fp->exit_handler` from the same freed object — an attacker-controlled function-pointer dispatch giving control-flow hijack and full kernel-integrity compromise.\nA:H - Even without weaponization, dereferencing and calling through the freed link produces a KASAN slab-use-after-free splat and a wild indirect branch — an immediate oops or panic — and the attacker can repeat the create/trigger/close cycle indefinitely." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "include/linux/bpf.h", "kernel/bpf/syscall.c", "kernel/trace/bpf_trace.c" ], "versions": [ { "version": "0dcac272540613d41c05e89679e4ddb978b612f1", "lessThan": "876941f533e7b47fc69977fc4551c02f2d18af97", "status": "affected", "versionType": "git" }, { "version": "0dcac272540613d41c05e89679e4ddb978b612f1", "lessThan": "5d8d447777564b35f67000e7838e7ccb64d525c8", "status": "affected", "versionType": "git" }, { "version": "0dcac272540613d41c05e89679e4ddb978b612f1", "lessThan": "1a80dbcb2dbaf6e4c216e62e30fa7d3daa8001ce", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "include/linux/bpf.h", "kernel/bpf/syscall.c", "kernel/trace/bpf_trace.c" ], "versions": [ { "version": "5.18", "status": "affected" }, { "version": "0", "lessThan": "5.18", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.26", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.8.5", "lessThanOrEqual": "6.8.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.9", "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": "5.18", "versionEndExcluding": "6.6.26" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.18", "versionEndExcluding": "6.8.5" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.18", "versionEndExcluding": "6.9" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/876941f533e7b47fc69977fc4551c02f2d18af97" }, { "url": "https://git.kernel.org/stable/c/5d8d447777564b35f67000e7838e7ccb64d525c8" }, { "url": "https://git.kernel.org/stable/c/1a80dbcb2dbaf6e4c216e62e30fa7d3daa8001ce" } ], "title": "bpf: support deferring bpf_link dealloc to after RCU grace period", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "providerMetadata": { "orgId": "af854a3a-2127-422b-91ae-364da2661108", "shortName": "CVE", "dateUpdated": "2024-08-02T03:21:48.532Z" }, "title": "CVE Program Container", "references": [ { "url": "https://git.kernel.org/stable/c/876941f533e7b47fc69977fc4551c02f2d18af97", "tags": [ "x_transferred" ] }, { "url": "https://git.kernel.org/stable/c/5d8d447777564b35f67000e7838e7ccb64d525c8", "tags": [ "x_transferred" ] }, { "url": "https://git.kernel.org/stable/c/1a80dbcb2dbaf6e4c216e62e30fa7d3daa8001ce", "tags": [ "x_transferred" ] } ] }, { "metrics": [ { "other": { "type": "ssvc", "content": { "id": "CVE-2024-35860", "role": "CISA Coordinator", "options": [ { "Exploitation": "none" }, { "Automatable": "no" }, { "Technical Impact": "partial" } ], "version": "2.0.3", "timestamp": "2024-09-10T15:41:33.868687Z" } } } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2024-09-11T17:33:17.617Z" } } ] } }