« Volver al listado

CVE-2026-86805

Estado: Pendiente de análisisMedia (6.3)—

A time-of-check to time-of-use (TOCTOU) race condition in the dynamic loader (ld.so) of the GNU C Library (glibc) versions 2.14 through 2.44 allows a local attacker to escalate privileges. When expanding $ORIGIN in DT_RPATH for setuid/setgid (AT_SECURE) programs, glibc validates the lexically normalized search path against the trusted directories but then opens the raw, un-normalized path.

Leer descripción completaMostrar menos

On systems where the Linux fs.protected_hardlinks sysctl is disabled, a local attacker who hard-links such a program into an attacker-controlled directory and wins a race to replace an intermediate path component with a symbolic link can direct the loader outside the trusted directory, causing it to load an attacker-controlled shared object and execute arbitrary code with the elevated privileges of the program.

Exploitation requires an installed setuid or setgid binary whose DT_RPATH uses $ORIGIN followed by ".." traversal that normalizes into a trusted directory, and the ability to hard-link that binary and win the race by swapping a path component for a symbolic link. Major Linux-based OS distributions ship with fs.protected_hardlinks enabled by default and mitigate the vulnerability.

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.

TOCTOU en cargador dinámico setuid/setgid permite escalada de privilegios local mediante race condition para cargar biblioteca compartida maliciosa, logrando ejecución de código arbitrario con permisos elevados (CWE-367, AV:L, PR:L).

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

Execution PreventionLimit Software InstallationAuditApplication Isolation and SandboxingAntivirus/AntimalwareExploit Protection

Tecnologías afectadas (1)

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

GNU — GlibcAI

CWE

Referencias

JSON original (NVD)

Mostrar
{
  "id": "CVE-2026-86805",
  "cveTags": [],
  "metrics": {
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-86805",
          "role": "CISA Coordinator",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "version": "2.0.3",
          "timestamp": "2026-09-22T00:00:00+00:00"
        }
      }
    ],
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "3ff69d7a-14f2-4f67-a097-88dee7810d18",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 6.3,
          "attackVector": "LOCAL",
          "baseSeverity": "MEDIUM",
          "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:L",
          "integrityImpact": "HIGH",
          "userInteraction": "REQUIRED",
          "attackComplexity": "HIGH",
          "availabilityImpact": "LOW",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 5.5,
        "exploitabilityScore": 0.8
      }
    ]
  },
  "affected": [
    {
      "source": "3ff69d7a-14f2-4f67-a097-88dee7810d18",
      "affectedData": [
        {
          "vendor": "The GNU C Library",
          "product": "glibc",
          "versions": [
            {
              "status": "affected",
              "version": "2.14",
              "lessThan": "2.45",
              "versionType": "custom"
            }
          ],
          "defaultStatus": "unaffected"
        }
      ]
    }
  ],
  "published": "2026-09-22T16:18:06.230",
  "references": [
    {
      "url": "https://sourceware.org/bugzilla/show_bug.cgi?id=34360",
      "source": "3ff69d7a-14f2-4f67-a097-88dee7810d18"
    },
    {
      "url": "https://sourceware.org/git/?p=glibc.git;a=blob_plain;f=advisories/GLIBC-SA-2026-0022",
      "source": "3ff69d7a-14f2-4f67-a097-88dee7810d18"
    }
  ],
  "vulnStatus": "Awaiting Analysis",
  "weaknesses": [
    {
      "type": "Secondary",
      "source": "3ff69d7a-14f2-4f67-a097-88dee7810d18",
      "description": [
        {
          "lang": "en",
          "value": "CWE-367"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "A time-of-check to time-of-use (TOCTOU) race condition in the dynamic loader (ld.so) of the GNU C Library (glibc) versions 2.14 through 2.44 allows a local attacker to escalate privileges. When expanding $ORIGIN in DT_RPATH for setuid/setgid (AT_SECURE) programs, glibc validates the lexically normalized search path against the trusted directories but then opens the raw, un-normalized path. On systems where the Linux fs.protected_hardlinks sysctl is disabled, a local attacker who hard-links such a program into an attacker-controlled directory and wins a race to replace an intermediate path component with a symbolic link can direct the loader outside the trusted directory, causing it to load an attacker-controlled shared object and execute arbitrary code with the elevated privileges of the program.\n\nExploitation requires an installed setuid or setgid binary whose DT_RPATH uses $ORIGIN followed by \"..\" traversal that normalizes into a trusted directory, and the ability to hard-link that binary and win the race by swapping a path component for a symbolic link. Major Linux-based OS distributions ship with fs.protected_hardlinks enabled by default and mitigate the vulnerability."
    }
  ],
  "lastModified": "2026-09-23T04:17:57.137",
  "sourceIdentifier": "3ff69d7a-14f2-4f67-a097-88dee7810d18"
}