{"cve":"CVE-2025-71109","nvd":{"published":"2026-01-14T15:15:59.973","modified":"2026-10-21T13:18:25.297","status":"Modified","description":"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\"), 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.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","score":5.5},"cwes":["CWE-787"],"references":["https://git.kernel.org/stable/c/36dac9a3dda1f2bae343191bc16b910c603cac25","https://git.kernel.org/stable/c/7f39b9d0e86ed6236b9a5fb67616ab1f76c4f150","https://git.kernel.org/stable/c/9cfda98cf02eacfa6b09076e98bd479fd73407c2","https://git.kernel.org/stable/c/e3e33ac2eb69d595079a1a1e444c2fb98efdd42d"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-22T16:41:11.231219466+00:00"},"epss":{"cve":"CVE-2025-71109","score":0.00226,"percentile":0.13201,"date":"2026-10-25"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}