{"id":"CVE-2024-50194","url":"https://www.cyber-defence.io/tools/cve/CVE-2024-50194","generatedAt":"2026-10-28T00:19:06.738Z","title":"In the Linux kernel, the following vulnerability has been resolved: arm64: probes: Fix uprobes for big-endian kernels The arm64 uprobes code is broken for big-endian kernels as it doesn't convert the in-memory instruction encoding (which is always…","description":"In the Linux kernel, the following vulnerability has been resolved:\n\narm64: probes: Fix uprobes for big-endian kernels\n\nThe arm64 uprobes code is broken for big-endian kernels as it doesn't\nconvert the in-memory instruction encoding (which is always\nlittle-endian) into the kernel's native endianness before analyzing and\nsimulating instructions. This may result in a few distinct problems:\n\n* The kernel may may erroneously reject probing an instruction which can\n  safely be probed.\n\n* The kernel may erroneously erroneously permit stepping an\n  instruction out-of-line when that instruction cannot be stepped\n  out-of-line safely.\n\n* The kernel may erroneously simulate instruction incorrectly dur to\n  interpretting the byte-swapped encoding.\n\nThe endianness mismatch isn't caught by the compiler or sparse because:\n\n* The arch_uprobe::{insn,ixol} fields are encoded as arrays of u8, so\n  the compiler and sparse have no idea these contain a little-endian\n  32-bit value. The core uprobes code populates these with a memcpy()\n  which similarly does not handle endianness.\n\n* While the uprobe_opcode_t type is an alias for __le32, both\n  arch_uprobe_analyze_insn() and arch_uprobe_skip_sstep() cast from u8[]\n  to the similarly-named probe_opcode_t, which is an alias for u32.\n  Hence there is no endianness conversion warning.\n\nFix this by changing the arch_uprobe::{insn,ixol} fields to __le32 and\nadding the appropriate __le32_to_cpu() conversions prior to consuming\nthe instruction encoding. The core uprobes copies these fields as opaque\nranges of bytes, and so is unaffected by this change.\n\nAt the same time, remove MAX_UINSN_BYTES and consistently use\nAARCH64_INSN_SIZE for clarity.\n\nTested with the following:\n\n| #include <stdio.h>\n| #include <stdbool.h>\n|\n| #define noinline __attribute__((noinline))\n|\n| static noinline void *adrp_self(void)\n| {\n|         void *addr;\n|\n|         asm volatile(\n|         \"       adrp    %x0, adrp_self\\n\"\n|         \"       add     %x0, %x0, :lo12:adrp_self\\n\"\n|         : \"=r\" (addr));\n| }\n|\n|\n| int main(int argc, char *argv)\n| {\n|         void *ptr = adrp_self();\n|         bool equal = (ptr == adrp_self);\n|\n|         printf(\"adrp_self   => %p\\n\"\n|                \"adrp_self() => %p\\n\"\n|                \"%s\\n\",\n|                adrp_self, ptr, equal ? \"EQUAL\" : \"NOT EQUAL\");\n|\n|         return 0;\n| }\n\n.... where the adrp_self() function was compiled to:\n\n| 00000000004007e0 <adrp_self>:\n|   4007e0:       90000000        adrp    x0, 400000 <__ehdr_start>\n|   4007e4:       911f8000        add     x0, x0, #0x7e0\n|   4007e8:       d65f03c0        ret\n\nBefore this patch, the ADRP is not recognized, and is assumed to be\nsteppable, resulting in corruption of the result:\n\n| # ./adrp-self\n| adrp_self   => 0x4007e0\n| adrp_self() => 0x4007e0\n| EQUAL\n| # echo 'p /root/adrp-self:0x007e0' > /sys/kernel/tracing/uprobe_events\n| # echo 1 > /sys/kernel/tracing/events/uprobes/enable\n| # ./adrp-self\n| adrp_self   => 0x4007e0\n| adrp_self() => 0xffffffffff7e0\n| NOT EQUAL\n\nAfter this patch, the ADRP is correctly recognized and simulated:\n\n| # ./adrp-self\n| adrp_self   => 0x4007e0\n| adrp_self() => 0x4007e0\n| EQUAL\n| #\n| # echo 'p /root/adrp-self:0x007e0' > /sys/kernel/tracing/uprobe_events\n| # echo 1 > /sys/kernel/tracing/events/uprobes/enable\n| # ./adrp-self\n| adrp_self   => 0x4007e0\n| adrp_self() => 0x4007e0\n| EQUAL","published":"2024-11-08T06:15:16.000Z","lastModified":"2026-06-17T08:03:50.000Z","status":"Modified","sourceIdentifier":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","cvss":{"version":"3.1","score":5.5,"severity":"MEDIUM","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"},"cwe":[],"affected":["linux/linux kernel"],"epss":{"score":0.00229,"percentile":0.13633,"date":"2026-10-26","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"low","text":"Lower severity and a low EPSS score (0.23%). Track it; it rarely justifies an emergency change on its own."},"changes":[],"references":[{"url":"https://git.kernel.org/stable/c/13f8f1e05f1dc36dbba6cba0ae03354c0dafcde7","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/14841bb7a531b96e2dde37423a3b33e75147c60d","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/3d2530c65be04e93720e30f191a7cf1a3aa8b51c","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/8165bf83b8a64be801d59cd2532b0d1ffed74d00","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/b6a638cb600e13f94b5464724eaa6ab7f3349ca2","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/cf60d19d40184e43d9a624e55a0da73be09e938d","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/cf9ddf9ed94c15564a05bbf6e9f18dffa0c7df80","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/e6ab336213918575124d6db43dc5d3554526242e","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://lists.debian.org/debian-lts-announce/2025/01/msg00001.html","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.debian.org/debian-lts-announce/2025/03/msg00002.html","source":"af854a3a-2127-422b-91ae-364da2661108"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2024-50194","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}