{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2024-47702", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2024-09-30T16:00:12.945Z", "datePublished": "2024-10-21T11:53:37.958Z", "dateUpdated": "2026-08-05T11:39:33.640Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T11:39:33.640Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fail verification for sign-extension of packet data/data_end/data_meta\n\nsyzbot reported a kernel crash due to\n commit 1f1e864b6555 (\"bpf: Handle sign-extenstin ctx member accesses\").\nThe reason is due to sign-extension of 32-bit load for\npacket data/data_end/data_meta uapi field.\n\nThe original code looks like:\n r2 = *(s32 *)(r1 + 76) /* load __sk_buff->data */\n r3 = *(u32 *)(r1 + 80) /* load __sk_buff->data_end */\n r0 = r2\n r0 += 8\n if r3 > r0 goto +1\n ...\nNote that __sk_buff->data load has 32-bit sign extension.\n\nAfter verification and convert_ctx_accesses(), the final asm code looks like:\n r2 = *(u64 *)(r1 +208)\n r2 = (s32)r2\n r3 = *(u64 *)(r1 +80)\n r0 = r2\n r0 += 8\n if r3 > r0 goto pc+1\n ...\nNote that 'r2 = (s32)r2' may make the kernel __sk_buff->data address invalid\nwhich may cause runtime failure.\n\nCurrently, in C code, typically we have\n void *data = (void *)(long)skb->data;\n void *data_end = (void *)(long)skb->data_end;\n ...\nand it will generate\n r2 = *(u64 *)(r1 +208)\n r3 = *(u64 *)(r1 +80)\n r0 = r2\n r0 += 8\n if r3 > r0 goto pc+1\n\nIf we allow sign-extension,\n void *data = (void *)(long)(int)skb->data;\n void *data_end = (void *)(long)skb->data_end;\n ...\nthe generated code looks like\n r2 = *(u64 *)(r1 +208)\n r2 <<= 32\n r2 s>>= 32\n r3 = *(u64 *)(r1 +80)\n r0 = r2\n r0 += 8\n if r3 > r0 goto pc+1\nand this will cause verification failure since \"r2 <<= 32\" is not allowed\nas \"r2\" is a packet pointer.\n\nTo fix this issue for case\n r2 = *(s32 *)(r1 + 76) /* load __sk_buff->data */\nthis patch added additional checking in is_valid_access() callback\nfunction for packet data/data_end/data_meta access. If those accesses\nare with sign-extenstion, the verification will fail.\n\n [1] https://lore.kernel.org/bpf/000000000000c90eee061d236d37@google.com/" } ], "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 by loading a crafted eBPF program through the bpf(BPF_PROG_LOAD) syscall, which requires local access to the system; the attacker supplies the malicious LDSX instruction, not a remote peer.\nAC:L - The attacker authors the BPF bytecode directly, so the verifier bypass is accepted deterministically on every load, and the corrupted `(s32)skb->data` pointer is produced on every execution of the program with no race or unpredictable precondition; running the hook repeatedly over many skbs makes the out-of-bounds dereference a certainty.\nPR:L - Loading the affected program types requires CAP_BPF/CAP_NET_ADMIN, which BPF token delegation (`bpf_token_capable()` → `bpf_ns_capable(token->userns, cap)`, present in the affected 6.9–6.11 range) makes available to a host-unprivileged user inside a user namespace, and CAP_BPF is by design a reduced privilege whose security boundary is the verifier itself.\nUI:N - The attacker loads and attaches the program and then generates the traffic (or uses BPF_PROG_TEST_RUN) that executes it; no action from any other user is needed.\nS:U - The out-of-bounds access and resulting corruption occur within the kernel's own security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - The verifier still tracks the truncated value as a valid PTR_TO_PACKET, so the program performs kernel-mode reads at `(s32)skb->data + K` far outside any packet buffer and can copy the results into a BPF map or the packet, giving an out-of-bounds kernel memory read primitive.\nI:H - `may_access_direct_pkt_data()` grants direct packet writes to SCHED_CLS, SCHED_ACT, XDP, LWT_XMIT and SK_SKB, so the same corrupted pointer yields kernel-mode stores at an attacker-influenced address — memory corruption exploitable for further escalation.\nA:H - syzbot reported this as a kernel crash; dereferencing the mangled address from softirq/NAPI context produces a page fault or general protection fault in kernel mode, oopsing or panicking the machine." } ] } ], "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/verifier.c", "net/core/filter.c" ], "versions": [ { "version": "1f1e864b65554e33fe74e3377e58b12f4302f2eb", "lessThan": "f1620c93a1ec950d87ef327a565d3907736d3340", "status": "affected", "versionType": "git" }, { "version": "1f1e864b65554e33fe74e3377e58b12f4302f2eb", "lessThan": "f09757fe97a225ae505886eac572e4cbfba96537", "status": "affected", "versionType": "git" }, { "version": "1f1e864b65554e33fe74e3377e58b12f4302f2eb", "lessThan": "92de36080c93296ef9005690705cba260b9bd68a", "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/verifier.c", "net/core/filter.c" ], "versions": [ { "version": "6.6", "status": "affected" }, { "version": "0", "lessThan": "6.6", "status": "unaffected", "versionType": "semver" }, { "version": "6.10.13", "lessThanOrEqual": "6.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.11.2", "lessThanOrEqual": "6.11.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12", "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": "6.6", "versionEndExcluding": "6.10.13" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.6", "versionEndExcluding": "6.11.2" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.6", "versionEndExcluding": "6.12" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/f1620c93a1ec950d87ef327a565d3907736d3340" }, { "url": "https://git.kernel.org/stable/c/f09757fe97a225ae505886eac572e4cbfba96537" }, { "url": "https://git.kernel.org/stable/c/92de36080c93296ef9005690705cba260b9bd68a" } ], "title": "bpf: Fail verification for sign-extension of packet data/data_end/data_meta", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "metrics": [ { "other": { "type": "ssvc", "content": { "id": "CVE-2024-47702", "role": "CISA Coordinator", "options": [ { "Exploitation": "none" }, { "Automatable": "no" }, { "Technical Impact": "partial" } ], "version": "2.0.3", "timestamp": "2024-10-21T13:04:24.861686Z" } } } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2024-10-21T13:14:13.443Z" } } ] } }