CVE-2024-50164

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2024-50164", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2024-10-21T19:36:19.962Z", "datePublished": "2024-11-07T09:31:41.012Z", "dateUpdated": "2026-11-10T12:33:36.097Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T11:42:12.665Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fix overloading of MEM_UNINIT's meaning\n\nLonial reported an issue in the BPF verifier where check_mem_size_reg()\nhas the following code:\n\n if (!tnum_is_const(reg->var_off))\n /* For unprivileged variable accesses, disable raw\n * mode so that the program is required to\n * initialize all the memory that the helper could\n * just partially fill up.\n */\n meta = NULL;\n\nThis means that writes are not checked when the register containing the\nsize of the passed buffer has not a fixed size. Through this bug, a BPF\nprogram can write to a map which is marked as read-only, for example,\n.rodata global maps.\n\nThe problem is that MEM_UNINIT's initial meaning that \"the passed buffer\nto the BPF helper does not need to be initialized\" which was added back\nin commit 435faee1aae9 (\"bpf, verifier: add ARG_PTR_TO_RAW_STACK type\")\ngot overloaded over time with \"the passed buffer is being written to\".\n\nThe problem however is that checks such as the above which were added later\nvia 06c1c049721a (\"bpf: allow helpers access to variable memory\") set meta\nto NULL in order force the user to always initialize the passed buffer to\nthe helper. Due to the current double meaning of MEM_UNINIT, this bypasses\nverifier write checks to the memory (not boundary checks though) and only\nassumes the latter memory is read instead.\n\nFix this by reverting MEM_UNINIT back to its original meaning, and having\nMEM_WRITE as an annotation to BPF helpers in order to then trigger the\nBPF verifier checks for writing to memory.\n\nSome notes: check_arg_pair_ok() ensures that for ARG_CONST_SIZE{,_OR_ZERO}\nwe can access fn->arg_type[arg - 1] since it must contain a preceding\nARG_PTR_TO_MEM. For check_mem_reg() the meta argument can be removed\naltogether since we do check both BPF_READ and BPF_WRITE. Same for the\nequivalent check_kfunc_mem_size_reg()."}], "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 through the bpf(2) syscall (BPF_MAP_CREATE/BPF_MAP_FREEZE/BPF_PROG_LOAD) by a process on the local system. Per kernel scoring guidance, BPF verifier bugs are Local.\nAC:L - The attacker fully authors the BPF program and the map contents; passing a non-constant size register to a helper such as bpf_skb_load_bytes() deterministically bypasses the write check every time. No race, timing window, or uncontrolled memory layout is involved.\nPR:L - An unprivileged local user can load a BPF_PROG_TYPE_SOCKET_FILTER program reaching bpf_skb_load_bytes() when kernel.unprivileged_bpf_disabled=0 (default on kernels without CONFIG_BPF_UNPRIV_DEFAULT_OFF, e.g. Android and many embedded builds), and CAP_BPF is delegable into unprivileged user namespaces via BPF tokens (bpf_token_capable() uses ns_capable). No real root in the init namespace is needed.\nUI:N - The attacker performs every step itself \u2014 creating and freezing the map, loading the program, and triggering it (e.g. by sending a packet to its own socket). No other user's action is required.\nS:U - The verifier bypass and its impact are both within the kernel's own security authority; this is a standard local privilege escalation with no VM, IOMMU, or hypervisor boundary crossed.\nC:H - Writing to a frozen BPF_F_RDONLY_PROG map desynchronizes the values the verifier constant-folded via bpf_map_direct_read()/__mark_reg_known() from the values used at runtime, so bounds the verifier proved safe become arbitrarily out-of-bounds, yielding an arbitrary kernel memory read primitive.\nI:H - The bug directly permits a BPF program to write into memory the verifier guarantees is immutable (.rodata global maps, PTR_TO_MAP_KEY, read-only PTR_TO_MEM/PTR_TO_BUF, and program context), and the resulting verifier invariant break escalates to an arbitrary kernel write and full privilege escalation.\nA:H - Out-of-bounds kernel reads and writes resulting from the broken verifier bounds reasoning readily corrupt kernel memory and panic the system, and the attacker can trigger this repeatedly."}]}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["kernel/bpf/verifier.c"], "versions": [{"version": "97e6d7dab1ca4648821c790a2b7913d6d5d549db", "lessThan": "43f4df339a4d375bedcad29a61ae6f0ee7a048f8", "status": "affected", "versionType": "git"}, {"version": "97e6d7dab1ca4648821c790a2b7913d6d5d549db", "lessThan": "48068ccaea957469f1adf78dfd2c1c9a7e18f0fe", "status": "affected", "versionType": "git"}, {"version": "97e6d7dab1ca4648821c790a2b7913d6d5d549db", "lessThan": "54bc31682660810af1bed7ca7a19f182df8d3df8", "status": "affected", "versionType": "git"}, {"version": "97e6d7dab1ca4648821c790a2b7913d6d5d549db", "lessThan": "8ea607330a39184f51737c6ae706db7fdca7628e", "status": "affected", "versionType": "git"}, {"version": "6099a6c8a749a5c8d5f8b4c4342022a92072a02b", "status": "affected", "versionType": "git"}, {"version": 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"en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fix overloading of MEM_UNINIT's meaning\n\nLonial reported an issue in the BPF verifier where check_mem_size_reg()\nhas the following code:\n\n if (!tnum_is_const(reg->var_off))\n /* For unprivileged variable accesses, disable raw\n * mode so that the program is required to\n * initialize all the memory that the helper could\n * just partially fill up.\n */\n meta = NULL;\n\nThis means that writes are not checked when the register containing the\nsize of the passed buffer has not a fixed size. Through this bug, a BPF\nprogram can write to a map which is marked as read-only, for example,\n.rodata global maps.\n\nThe problem is that MEM_UNINIT's initial meaning that \"the passed buffer\nto the BPF helper does not need to be initialized\" which was added back\nin commit 435faee1aae9 (\"bpf, verifier: add ARG_PTR_TO_RAW_STACK type\")\ngot overloaded over time with \"the passed buffer is being written to\".\n\nThe problem however is that checks such as the above which were added later\nvia 06c1c049721a (\"bpf: allow helpers access to variable memory\") set meta\nto NULL in order force the user to always initialize the passed buffer to\nthe helper. Due to the current double meaning of MEM_UNINIT, this bypasses\nverifier write checks to the memory (not boundary checks though) and only\nassumes the latter memory is read instead.\n\nFix this by reverting MEM_UNINIT back to its original meaning, and having\nMEM_WRITE as an annotation to BPF helpers in order to then trigger the\nBPF verifier checks for writing to memory.\n\nSome notes: check_arg_pair_ok() ensures that for ARG_CONST_SIZE{,_OR_ZERO}\nwe can access fn->arg_type[arg - 1] since it must contain a preceding\nARG_PTR_TO_MEM. For check_mem_reg() the meta argument can be removed\naltogether since we do check both BPF_READ and BPF_WRITE. Same for the\nequivalent check_kfunc_mem_size_reg()."}, {"lang": "es", "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: bpf: Se corrige la sobrecarga del significado de MEM_UNINIT Lonial inform\u00f3 de un problema en el verificador BPF donde check_mem_size_reg() tiene el siguiente c\u00f3digo: if (!tnum_is_const(reg->var_off)) /* Para accesos a variables sin privilegios, deshabilitar el modo sin formato * para que el programa deba * inicializar toda la memoria que el ayudante podr\u00eda * llenar parcialmente. */ meta = NULL; Esto significa que las escrituras no se verifican cuando el registro que contiene el tama\u00f1o del b\u00fafer pasado no tiene un tama\u00f1o fijo. A trav\u00e9s de este error, un programa BPF puede escribir en un mapa que est\u00e1 marcado como de solo lectura, por ejemplo, mapas globales .rodata. El problema es que el significado inicial de MEM_UNINIT de que \"el buffer pasado al ayudante BPF no necesita ser inicializado\" que se agreg\u00f3 en el commit 435faee1aae9 (\"bpf, verificador: agregar tipo ARG_PTR_TO_RAW_STACK\") se sobrecarg\u00f3 con el tiempo con \"se est\u00e1 escribiendo en el b\u00fafer pasado\". Sin embargo, el problema es que las comprobaciones como la anterior que se agregaron m\u00e1s tarde a trav\u00e9s de 06c1c049721a (\"bpf: permitir que los ayudantes accedan a la memoria variable\") establecen meta en NULL para obligar al usuario a inicializar siempre el b\u00fafer pasado al ayudante. Debido al doble significado actual de MEM_UNINIT, esto omite las comprobaciones de escritura del verificador en la memoria (aunque no las comprobaciones de los l\u00edmites) y solo supone que se lee la \u00faltima memoria en su lugar. Solucione esto revirtiendo MEM_UNINIT a su significado original y haciendo que MEM_WRITE sea una anotaci\u00f3n para los ayudantes de BPF para luego activar las comprobaciones del verificador de BPF para escribir en la memoria. Algunas notas: check_arg_pair_ok() garantiza que para ARG_CONST_SIZE{,_OR_ZERO} podamos acceder a fn->arg_type[arg - 1] ya que debe contener un ARG_PTR_TO_MEM anterior. Para check_mem_reg(), el argumento meta se puede eliminar por completo ya que verificamos tanto BPF_READ como BPF_WRITE. Lo mismo para el check_kfunc_mem_size_reg() equivalente."}], "id": "CVE-2024-50164", "lastModified": "2026-11-10T13:17:25.340", "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"}, {"cvssData": {"attackComplexity": "LOW", "attackVector": "LOCAL", "availabilityImpact": "HIGH", "baseScore": 7.1, "baseSeverity": "HIGH", "confidentialityImpact": "NONE", "integrityImpact": "HIGH", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 1.8, "impactScore": 5.2, "source": "nvd@nist.gov", "type": "Primary"}]}, "published": "2024-11-07T10:15:07.697", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/43f4df339a4d375bedcad29a61ae6f0ee7a048f8"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/48068ccaea957469f1adf78dfd2c1c9a7e18f0fe"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/54bc31682660810af1bed7ca7a19f182df8d3df8"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/8ea607330a39184f51737c6ae706db7fdca7628e"}, {"source": "af854a3a-2127-422b-91ae-364da2661108", "url": "https://lists.debian.org/debian-lts-announce/2025/03/msg00001.html"}, {"source": "0b142b55-0307-4c5a-b3c9-f314f3fb7c5e", "url": "https://cert-portal.siemens.com/productcert/html/ssa-019113.html"}, {"source": "0b142b55-0307-4c5a-b3c9-f314f3fb7c5e", "url": "https://cert-portal.siemens.com/productcert/html/ssa-457936.html"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Modified", "weaknesses": [{"description": [{"lang": "en", "value": "NVD-CWE-noinfo"}], "source": "nvd@nist.gov", "type": "Primary"}]}

{"bugzilla": {"description": "kernel: bpf: Fix overloading of MEM_UNINIT's meaning", "id": "2324322", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2324322"}, "csaw": false, "cvss3": {"cvss3_base_score": "6.7", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H", "status": "draft"}, "cwe": "CWE-99", "details": ["In the Linux kernel, the following vulnerability has been resolved:\nbpf: Fix overloading of MEM_UNINIT's meaning\nLonial reported an issue in the BPF verifier where check_mem_size_reg()\nhas the following code:\nif (!tnum_is_const(reg->var_off))\n/* For unprivileged variable accesses, disable raw\n* mode so that the program is required to\n* initialize all the memory that the helper could\n* just partially fill up.\n*/\nmeta = NULL;\nThis means that writes are not checked when the register containing the\nsize of the passed buffer has not a fixed size. Through this bug, a BPF\nprogram can write to a map which is marked as read-only, for example,\n.rodata global maps.\nThe problem is that MEM_UNINIT's initial meaning that \"the passed buffer\nto the BPF helper does not need to be initialized\" which was added back\nin commit 435faee1aae9 (\"bpf, verifier: add ARG_PTR_TO_RAW_STACK type\")\ngot overloaded over time with \"the passed buffer is being written to\".\nThe problem however is that checks such as the above which were added later\nvia 06c1c049721a (\"bpf: allow helpers access to variable memory\") set meta\nto NULL in order force the user to always initialize the passed buffer to\nthe helper. Due to the current double meaning of MEM_UNINIT, this bypasses\nverifier write checks to the memory (not boundary checks though) and only\nassumes the latter memory is read instead.\nFix this by reverting MEM_UNINIT back to its original meaning, and having\nMEM_WRITE as an annotation to BPF helpers in order to then trigger the\nBPF verifier checks for writing to memory.\nSome notes: check_arg_pair_ok() ensures that for ARG_CONST_SIZE{,_OR_ZERO}\nwe can access fn->arg_type[arg - 1] since it must contain a preceding\nARG_PTR_TO_MEM. For check_mem_reg() the meta argument can be removed\naltogether since we do check both BPF_READ and BPF_WRITE. Same for the\nequivalent check_kfunc_mem_size_reg()."], "name": "CVE-2024-50164", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Out of support scope", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Out of support scope", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Will not fix", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Will not fix", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 9"}], "public_date": "2024-11-07T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2024-50164\nhttps://nvd.nist.gov/vuln/detail/CVE-2024-50164\nhttps://lore.kernel.org/linux-cve-announce/2024110748-CVE-2024-50164-b109@gregkh/T"], "statement": "The default Red Hat Enterprise Linux kernel prevents unprivileged users from being able to use eBPF by the kernel.unprivileged_bpf_disabled sysctl. This would require a privileged user with CAP_SYS_ADMIN or root to be able to abuse this flaw reducing its attack space.\nFor the Red Hat Enterprise Linux 9 to confirm the current state, inspect the sysctl with the command:\ncat /proc/sys/kernel/unprivileged_bpf_disabled\nThe setting of 1 would mean that unprivileged users can not use eBPF, mitigating the flaw.", "threat_severity": "Moderate"}

{}