{
  "cveId": "CVE-2026-89923",
  "url": "https://patchblox.com/security/cve/CVE-2026-89923",
  "summary": "CVE-2026-89923 is fixed in 2 products on 1 platform, first by DEBIAN-CVE-2026-89923, released September 23, 2026. It is not reported as exploited. Patch Radar priority: High.",
  "title": "KVM: s390: Free guest debug data on vcpu destroy",
  "description": "In the Linux kernel, the following vulnerability has been resolved:  KVM: s390: Free guest debug data on vcpu destroy  kvm_s390_clear_bp_data() is only called from kvm_arch_vcpu_ioctl_set_guest_debug(), i.e. when user space changes or disables debugging. A vCPU that is destroyed while hardware breakpoints are still armed - the normal case when the VMM just exits or crashes - leaks hw_bp_info, hw_wp_info and all old_data buffers, since generic KVM frees the vCPU right after kvm_arch_vcpu_destroy().  That is bounded by MAX_BP_COUNT entries, so roughly 8 KiB per vCPU, but it is unbounded over VM lifetimes. The allocations are GFP_KERNEL_ACCOUNT, so the charge also outlives the exiting process and pins dying memcgs.  Fix by clearing the debug data on vCPU destruction. Calling it unconditionally is fine: struct kvm_vcpu is zero allocated, so for a vCPU that never enabled debugging the counters are 0 and the pointers NULL.",
  "published": "2026-09-16T11:17:01Z",
  "severity": "Moderate",
  "cvss": 7.1,
  "epss": 0.00216,
  "epssPercentile": 0.1214,
  "priority": "High",
  "priorityTier": 3,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "vendorAdvisory": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-89923",
  "fixes": [
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 12.15 (bookworm)",
      "fixedVersion": "6.1.190-1",
      "fix": "DEBIAN-CVE-2026-89923",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-89923",
      "released": "2026-09-23T19:19:02Z"
    },
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 13.5 (trixie)",
      "fixedVersion": "6.12.111-1",
      "fix": "DEBIAN-CVE-2026-89923",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-89923",
      "released": "2026-09-23T19:19:02Z"
    },
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 14",
      "fixedVersion": "7.2.6-1",
      "fix": "DEBIAN-CVE-2026-89923",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-89923",
      "released": "2026-09-23T19:19:02Z"
    },
    {
      "platform": "linux",
      "product": "linux-6.12",
      "release": "Debian 12.15 (bookworm)",
      "fixedVersion": "6.12.111-1~deb12u1",
      "fix": "DEBIAN-CVE-2026-89923",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-89923",
      "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"
  }
}