{
  "cveId": "CVE-2025-71109",
  "url": "https://patchblox.com/security/cve/CVE-2025-71109",
  "summary": "CVE-2025-71109 is fixed in linux on 1 platform, first by DEBIAN-CVE-2025-71109, released January 14, 2026. It is not reported as exploited. Patch Radar priority: High.",
  "title": "MIPS: ftrace: Fix memory corruption when kernel is located beyond 32 bits",
  "description": "In the Linux kernel, the following vulnerability has been resolved:  MIPS: ftrace: Fix memory corruption when kernel is located beyond 32 bits  Since commit e424054000878 (\u0022MIPS: Tracing: Reduce the overhead of dynamic Function Tracer\u0022), the macro UASM_i_LA_mostly has been used, and this macro can generate more than 2 instructions. At the same time, the code in ftrace assumes that no more than 2 instructions can be generated, which is why it stores them in an int[2] array. However, as previously noted, the macro UASM_i_LA_mostly (and now UASM_i_LA) causes a buffer overflow when _mcount is beyond 32 bits. This leads to corruption of the variables located in the __read_mostly section.  This corruption was observed because the variable __cpu_primary_thread_mask was corrupted, causing a hang very early during boot.  This fix prevents the corruption by avoiding the generation of instructions if they could exceed 2 instructions in length. Fortunately, insn_la_mcount is only used if the instrumented code is located outside the kernel code section, so dynamic ftrace can still be used, albeit in a more limited scope. This is still preferable to corrupting memory and/or crashing the kernel.",
  "published": "2026-01-14T15:15:59Z",
  "severity": "Important",
  "cvss": 7.8,
  "cvssVector": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
  "epss": 0.00226,
  "epssPercentile": 0.13398,
  "priority": "High",
  "priorityTier": 3,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "vendorAdvisory": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-71109",
  "fixes": [
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 13.5 (trixie)",
      "fixedVersion": "6.12.69-1",
      "fix": "DEBIAN-CVE-2025-71109",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2025-71109",
      "released": "2026-01-14T15:15:59Z"
    },
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 14",
      "fixedVersion": "6.18.3-1",
      "fix": "DEBIAN-CVE-2025-71109",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2025-71109",
      "released": "2026-01-14T15:15:59Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-08T13:06:02Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}