{"id":"CVE-2025-71109","title":"MIPS: ftrace: Fix memory corruption when kernel is located beyond 32 bits","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nMIPS: ftrace: Fix memory corruption when kernel is located beyond 32 bits\n\nSince commit e424054000878 (\"MIPS: Tracing: Reduce the overhead of\ndynamic Function Tracer\"),…","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","cvssSource":"cna","vendor":"Linux","product":"Linux","affected":["Linux >= e424054000878d7eb11e44289242886d6e219d22 < 9cfda98cf02eacfa6b09076e98bd479fd73407c2","Linux >= e424054000878d7eb11e44289242886d6e219d22 < e3e33ac2eb69d595079a1a1e444c2fb98efdd42d","Linux >= e424054000878d7eb11e44289242886d6e219d22 < 7f39b9d0e86ed6236b9a5fb67616ab1f76c4f150","Linux >= e424054000878d7eb11e44289242886d6e219d22 < 36dac9a3dda1f2bae343191bc16b910c603cac25","Linux 2.6.35"],"published":"2026-01-14","updated":"2026-10-21","sourceUpdated":"2026-10-21T12:38:34.366Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2025-71109","references":[{"url":"https://git.kernel.org/stable/c/9cfda98cf02eacfa6b09076e98bd479fd73407c2"},{"url":"https://git.kernel.org/stable/c/e3e33ac2eb69d595079a1a1e444c2fb98efdd42d"},{"url":"https://git.kernel.org/stable/c/7f39b9d0e86ed6236b9a5fb67616ab1f76c4f150"},{"url":"https://git.kernel.org/stable/c/36dac9a3dda1f2bae343191bc16b910c603cac25"}],"tags":["cve.org"],"epss":0.00226,"epssPercentile":0.13245,"ingestedAt":"2026-10-21T12:48:53.676Z","slug":"CVE-2025-71109","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nMIPS: ftrace: Fix memory corruption when kernel is located beyond 32 bits\n\nSince commit e424054000878 (\"MIPS: Tracing: Reduce the overhead of\ndynamic Function Tracer\"), the macro UASM_i_LA_mostly has been used,\nand this macro can generate more than 2 instructions. At the same\ntime, the code in ftrace assumes that no more than 2 instructions can\nbe generated, which is why it stores them in an int[2] array. However,\nas previously noted, the macro UASM_i_LA_mostly (and now UASM_i_LA)\ncauses a buffer overflow when _mcount is beyond 32 bits. This leads to\ncorruption of the variables located in the __read_mostly section.\n\nThis corruption was observed because the variable\n__cpu_primary_thread_mask was corrupted, causing a hang very early\nduring boot.\n\nThis fix prevents the corruption by avoiding the generation of\ninstructions if they could exceed 2 instructions in\nlength. Fortunately, insn_la_mcount is only used if the instrumented\ncode is located outside the kernel code section, so dynamic ftrace can\nstill be used, albeit in a more limited scope. This is still\npreferable to corrupting memory and/or crashing the kernel.\n\n## Affected\n\n- `Linux >= e424054000878d7eb11e44289242886d6e219d22 < 9cfda98cf02eacfa6b09076e98bd479fd73407c2`\n- `Linux >= e424054000878d7eb11e44289242886d6e219d22 < e3e33ac2eb69d595079a1a1e444c2fb98efdd42d`\n- `Linux >= e424054000878d7eb11e44289242886d6e219d22 < 7f39b9d0e86ed6236b9a5fb67616ab1f76c4f150`\n- `Linux >= e424054000878d7eb11e44289242886d6e219d22 < 36dac9a3dda1f2bae343191bc16b910c603cac25`\n- `Linux 2.6.35`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":39,"depthScoreParts":{"impact":39.1,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}