{
  "cveId": "CVE-2026-90136",
  "url": "https://patchblox.com/security/cve/CVE-2026-90136",
  "summary": "CVE-2026-90136 is fixed in 11 products on 1 platform, first by DEBIAN-CVE-2026-90136, released September 23, 2026. It is not reported as exploited. Patch Radar priority: Routine.",
  "title": "platform/x86/amd/hsmp: Reject negative power cap writes in hwmon",
  "description": "In the Linux kernel, the following vulnerability has been resolved:  platform/x86/amd/hsmp: Reject negative power cap writes in hwmon  hsmp_hwmon_write() takes the user-supplied hwmon value as a signed long and assigns \u0022val / MICROWATT_PER_MILLIWATT\u0022 to msg.args[0], which is a __u32.  MICROWATT_PER_MILLIWATT is an unsigned long, so a negative write to power1_cap (e.g. \u0022echo -1 \u003E power1_cap\u0022) is first converted to a huge unsigned value by the division and then stored into the u32 argument.  As a result a nonsensical, multi-gigawatt socket power limit is sent to the SMU via HSMP_SET_SOCKET_POWER_LIMIT instead of the write being rejected.  Reject negative values with -EINVAL before the conversion.  Tested with HSMP enabled:    CAP=$(dirname $(grep -l amd_hsmp_hwmon \\         /sys/class/hwmon/hwmon*/name | head -1))/power1_cap    # negative write   echo -1000000 \u003E $CAP ; echo \u0022ret=$?\u0022   # valid positive write must still work   echo 400000000 \u003E $CAP ; echo \u0022ret=$?\u0022  Before:   # echo -1000000 \u003E $CAP ; echo \u0022ret=$?\u0022   ret=0                             \u003C- accepted; bogus limit sent to SMU   # echo 400000000 \u003E $CAP ; echo \u0022ret=$?\u0022   ret=0  After:   # echo -1000000 \u003E $CAP ; echo \u0022ret=$?\u0022   bash: echo: write error: Invalid argument   ret=1                             \u003C- rejected with -EINVAL   # echo 400000000 \u003E $CAP ; echo \u0022ret=$?\u0022   ret=0                             \u003C- valid write still works",
  "published": "2026-09-17T17:17:06Z",
  "severity": "",
  "epss": 0.00206,
  "epssPercentile": 0.10793,
  "priority": "Routine",
  "priorityTier": 4,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "vendorAdvisory": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-90136",
  "fixes": [
    {
      "platform": "linux",
      "product": "kernel-64kb",
      "release": "sles 15.7",
      "fixedVersion": "6.4.0-150700.53.90.1",
      "fix": "SUSE-SU-2026:5091-1",
      "url": "https://patchblox.com/security/fix/linux/suse-su-2026-5091-1",
      "released": "2026-11-07T00:43:02Z"
    },
    {
      "platform": "linux",
      "product": "kernel-azure",
      "release": "sles 15.7",
      "fixedVersion": "6.4.0-150700.53.90.1",
      "fix": "SUSE-SU-2026:5091-1",
      "url": "https://patchblox.com/security/fix/linux/suse-su-2026-5091-1",
      "released": "2026-11-07T00:43:02Z"
    },
    {
      "platform": "linux",
      "product": "kernel-default",
      "release": "sles 15.7",
      "fixedVersion": "6.4.0-150700.53.90.1",
      "fix": "SUSE-SU-2026:5091-1",
      "url": "https://patchblox.com/security/fix/linux/suse-su-2026-5091-1",
      "released": "2026-11-07T00:43:02Z"
    },
    {
      "platform": "linux",
      "product": "kernel-default-base",
      "release": "sles 15.7",
      "fixedVersion": "6.4.0-150700.53.90.1.150700.17.51.1",
      "fix": "SUSE-SU-2026:5091-1",
      "url": "https://patchblox.com/security/fix/linux/suse-su-2026-5091-1",
      "released": "2026-11-07T00:43:02Z"
    },
    {
      "platform": "linux",
      "product": "kernel-docs",
      "release": "sles 15.7",
      "fixedVersion": "6.4.0-150700.53.90.1",
      "fix": "SUSE-SU-2026:5091-1",
      "url": "https://patchblox.com/security/fix/linux/suse-su-2026-5091-1",
      "released": "2026-11-07T00:43:02Z"
    },
    {
      "platform": "linux",
      "product": "kernel-livepatch-SLE15-SP7_Update_24",
      "release": "sles 15.7",
      "fixedVersion": "1-150700.15.3.1",
      "fix": "SUSE-SU-2026:5091-1",
      "url": "https://patchblox.com/security/fix/linux/suse-su-2026-5091-1",
      "released": "2026-11-07T00:43:02Z"
    },
    {
      "platform": "linux",
      "product": "kernel-obs-build",
      "release": "sles 15.7",
      "fixedVersion": "6.4.0-150700.53.90.1",
      "fix": "SUSE-SU-2026:5091-1",
      "url": "https://patchblox.com/security/fix/linux/suse-su-2026-5091-1",
      "released": "2026-11-07T00:43:02Z"
    },
    {
      "platform": "linux",
      "product": "kernel-source",
      "release": "sles 15.7",
      "fixedVersion": "6.4.0-150700.53.90.1",
      "fix": "SUSE-SU-2026:5091-1",
      "url": "https://patchblox.com/security/fix/linux/suse-su-2026-5091-1",
      "released": "2026-11-07T00:43:02Z"
    },
    {
      "platform": "linux",
      "product": "kernel-syms",
      "release": "sles 15.7",
      "fixedVersion": "6.4.0-150700.53.90.1",
      "fix": "SUSE-SU-2026:5091-1",
      "url": "https://patchblox.com/security/fix/linux/suse-su-2026-5091-1",
      "released": "2026-11-07T00:43:02Z"
    },
    {
      "platform": "linux",
      "product": "kernel-zfcpdump",
      "release": "sles 15.7",
      "fixedVersion": "6.4.0-150700.53.90.1",
      "fix": "SUSE-SU-2026:5091-1",
      "url": "https://patchblox.com/security/fix/linux/suse-su-2026-5091-1",
      "released": "2026-11-07T00:43:02Z"
    },
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 14",
      "fixedVersion": "7.2.6-1",
      "fix": "DEBIAN-CVE-2026-90136",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-90136",
      "released": "2026-09-23T19:19:02Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-08T06:59:42Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}