{"id":"CVE-2024-50164","title":"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(re…","summary":"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(re…","severity":"high","cvss":7.1,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H","vendor":"linux","product":"linux_kernel","affected":["linux_kernel >= 5.19, < 6.6.59","linux_kernel >= 6.7, < 6.11.6","linux_kernel = 6.12"],"patched":["linux_kernel 6.11.6"],"published":"2024-11-07","updated":"2026-07-14","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2024-50164","references":[{"url":"https://git.kernel.org/stable/c/43f4df339a4d375bedcad29a61ae6f0ee7a048f8","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/48068ccaea957469f1adf78dfd2c1c9a7e18f0fe","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/54bc31682660810af1bed7ca7a19f182df8d3df8","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/8ea607330a39184f51737c6ae706db7fdca7628e","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://lists.debian.org/debian-lts-announce/2025/03/msg00001.html","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-019113.html","label":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2024/cve-2024-50164.json"},{"url":"https://access.redhat.com/security/cve/CVE-2024-50164"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2324322"},{"url":"https://www.cve.org/CVERecord?id=CVE-2024-50164"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2024-50164"},{"url":"https://lore.kernel.org/linux-cve-announce/2024110748-CVE-2024-50164-b109@gregkh/T"}],"tags":["nvd","cve.org","csaf","vex","red-hat"],"epss":0.00214,"epssPercentile":0.12026,"ingestedAt":"2026-07-14T13:36:54.674Z","cwe":["CWE-99"],"scores":{"nvd":7.1,"vendor":6.7},"slug":"CVE-2024-50164","body":"## Overview\n\nIn 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().\n\n## Affected\n\n- `linux_kernel >= 5.19, < 6.6.59`\n- `linux_kernel >= 6.7, < 6.11.6`\n- `linux_kernel = 6.12`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `linux_kernel 6.11.6`\n\n## Vendor advisories\n\n- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 9 · no fix planned: Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 9 · updated 2026-09-14 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2024/cve-2024-50164.json)","depth":"twilight","depthScore":39,"depthScoreParts":{"impact":39.1,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}