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CVE-2026-89459

Estado: RecibidaAlta (7)—

In the Linux kernel, the following vulnerability has been resolved:

s390/percpu: Fix MVIY_PERCPU() with older binutils

Commit a737737cdb9c ("s390/percpu: Infrastructure for more efficient this_cpu operations") introduced MVIY_PERCPU(), which stringifies arguments that are already C string literals. This generates an assembler macro invocation with whitespace-separated quoted arguments:

GNU as versions prior to binutils 2.39 drop the separating whitespace between quoted macro arguments during input scrubbing. They consequently parse the invocation as a single argument and emit repeated warnings:

The .ifc in GEN_MVIY never matches and GNU as exits successfully without emitting the mviy instruction.

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As a result, the interrupted per-CPU sequence is not marked in lowcore and the exception return path cannot repair the per-CPU address register after migration.

All MVIY_PERCPU() callers pass C string literals. Use them directly and separate the assembler macro arguments with an explicit comma. The resulting invocation is:

This form is unambiguous for GNU as and LLVM's integrated assembler. This behavior was fixed in GNU as from binutils 2.39, but Linux supports binutils 2.30.

Detalles técnicos trazas, registros y código del informe original
  GEN_MVIY "459712" "%r3"

  Warning: missing closing `"'

  GEN_MVIY 459712, %r3

CVSS

Probabilidad de explotación (EPSS)

EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).

🎯 Técnicas ATT&CK

Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.

Vulnerabilidad local (AV:L) con privilegios requeridos (PR:L) que permite ejecución de código no autorizado en el kernel s390 mediante instrucción MVIY ausente, escalando privilegios.

Inferido por nuestro agente de análisis a partir de la descripción oficial, el vector CVSS y la CWE, y comprobado por un supervisor. Puede contener errores.

🛡️ Mitigaciones ATT&CK que cubren estas técnicas

Tecnologías afectadas (1)

⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.

Referencias

JSON original (NVD)

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{
  "id": "CVE-2026-89459",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 7,
          "attackVector": "LOCAL",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "HIGH",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 5.9,
        "exploitabilityScore": 1
      }
    ]
  },
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "a737737cdb9c94e40a9926cdc2320f874c05d709",
              "lessThan": "91770b08a120967077ae78600612f18bc5ee3caf",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "a737737cdb9c94e40a9926cdc2320f874c05d709",
              "lessThan": "101782f8945a125044347312d74d488c05741c4a",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "arch/s390/include/asm/percpu.h"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "7.2"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "7.2",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "7.2.4",
              "versionType": "semver",
              "lessThanOrEqual": "7.2.*"
            },
            {
              "status": "unaffected",
              "version": "7.3-rc1",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "arch/s390/include/asm/percpu.h"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-09-11T20:19:26.780",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/101782f8945a125044347312d74d488c05741c4a",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/91770b08a120967077ae78600612f18bc5ee3caf",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Received",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ns390/percpu: Fix MVIY_PERCPU() with older binutils\n\nCommit a737737cdb9c (\"s390/percpu: Infrastructure for more efficient\nthis_cpu operations\") introduced MVIY_PERCPU(), which stringifies\narguments that are already C string literals. This generates an\nassembler macro invocation with whitespace-separated quoted arguments:\n\n  GEN_MVIY \"459712\" \"%r3\"\n\nGNU as versions prior to binutils 2.39 drop the separating whitespace\nbetween quoted macro arguments during input scrubbing. They\nconsequently parse the invocation as a single argument and emit\nrepeated warnings:\n\n  Warning: missing closing `\"'\n\nThe .ifc in GEN_MVIY never matches and GNU as exits successfully\nwithout emitting the mviy instruction. As a result, the interrupted\nper-CPU sequence is not marked in lowcore and the exception return\npath cannot repair the per-CPU address register after migration.\n\nAll MVIY_PERCPU() callers pass C string literals. Use them directly\nand separate the assembler macro arguments with an explicit comma. The\nresulting invocation is:\n\n  GEN_MVIY 459712, %r3\n\nThis form is unambiguous for GNU as and LLVM's integrated assembler.\nThis behavior was fixed in GNU as from binutils 2.39, but Linux\nsupports binutils 2.30."
    }
  ],
  "lastModified": "2026-09-13T07:17:09.733",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}