{
  "cveId": "CVE-2026-90211",
  "url": "https://patchblox.com/security/cve/CVE-2026-90211",
  "summary": "CVE-2026-90211 is fixed in linux on 1 platform by DEBIAN-CVE-2026-90211 (version 7.2.6-1), released September 23, 2026. It is not reported as exploited. Patch Radar priority: Routine.",
  "title": "bpf, s390: Clear fetch destination on faulting arena atomic",
  "description": "In the Linux kernel, the following vulnerability has been resolved:  bpf, s390: Clear fetch destination on faulting arena atomic  Same missing register clear as on riscv64. A RMW atomic on an arena pointer is converted to BPF_PROBE_ATOMIC and gets an exception table entry, but bpf_jit_probe_atomic_pre() only fills in the arena base and the probe offset, leaving probe-\u003Ereg at the -1 that bpf_jit_probe_init() set, which bpf_jit_probe_post() writes into the entry and ex_handler_bpf() then reads back as \u0022there is nothing to clear\u0022.  That is right for a plain BPF_{ADD,AND,OR,XOR}, which only writes memory, but an RMW carrying BPF_FETCH also reads the old value into a register: src_reg for BPF_{ADD,AND,OR,XOR} | BPF_FETCH and BPF_XCHG, and r0 for BPF_CMPXCHG. So on a fault over an unmapped arena page the program resumes at the landing pad with whatever that register held before the atomic instead of the 0 that every other BPF_PROBE_* access delivers.  Fill probe-\u003Ereg in from bpf_atomic_load_reg(). Unlike x86-64 and arm64, s390x does not report arena violations from its exception handler, so there is no access direction to correct here, only the missing register clear.",
  "published": "2026-09-17T17:17:16Z",
  "severity": "",
  "epss": 0.00198,
  "epssPercentile": 0.09577,
  "priority": "Routine",
  "priorityTier": 4,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "vendorAdvisory": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-90211",
  "fixes": [
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 14",
      "fixedVersion": "7.2.6-1",
      "fix": "DEBIAN-CVE-2026-90211",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-90211",
      "released": "2026-09-23T19:19:02Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-09T01:18:40Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}