FKIE_CVE-2026-3591

Vulnerability from fkie_nvd - Published: 2026-03-25 14:16 - Updated: 2026-03-25 15:41
Severity ?
5.4 (Medium) - CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N
Summary
A use-after-return vulnerability exists in the `named` server when handling DNS queries signed with SIG(0). Using a specially-crafted DNS request, an attacker may be able to cause an ACL to improperly (mis)match an IP address. In a default-allow ACL (denying only specific IP addresses), this may lead to unauthorized access. Default-deny ACLs should fail-secure. This issue affects BIND 9 versions 9.20.0 through 9.20.20, 9.21.0 through 9.21.19, and 9.20.9-S1 through 9.20.20-S1. BIND 9 versions 9.18.0 through 9.18.46 and 9.18.11-S1 through 9.18.46-S1 are NOT affected.
References
security-officer@isc.orghttps://downloads.isc.org/isc/bind9/9.20.21
security-officer@isc.orghttps://downloads.isc.org/isc/bind9/9.21.20
security-officer@isc.orghttps://kb.isc.org/docs/cve-2026-3591
Impacted products
Vendor Product Version
To clipboard 

{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "A use-after-return vulnerability exists in the `named` server when handling DNS queries signed with SIG(0). Using a specially-crafted DNS request, an attacker may be able to cause an ACL to improperly (mis)match an IP address. In a default-allow ACL (denying only specific IP addresses), this may lead to unauthorized access. Default-deny ACLs should fail-secure.\nThis issue affects BIND 9 versions 9.20.0 through 9.20.20, 9.21.0 through 9.21.19, and 9.20.9-S1 through 9.20.20-S1.\nBIND 9 versions 9.18.0 through 9.18.46 and 9.18.11-S1 through 9.18.46-S1 are NOT affected."
    },
    {
      "lang": "es",
      "value": "Una vulnerabilidad de use-after-return existe en el servidor \u0027named\u0027 al manejar consultas DNS firmadas con SIG(0). Usando una solicitud DNS especialmente dise\u00f1ada, un atacante podr\u00eda ser capaz de hacer que una ACL haga una coincidencia incorrecta con una direcci\u00f3n IP. En una ACL de permiso predeterminado (negando solo direcciones IP espec\u00edficas), esto podr\u00eda llevar a acceso no autorizado. Las ACL de denegaci\u00f3n predeterminada deber\u00edan fallar de forma segura.\nEste problema afecta a las versiones de BIND 9 9.20.0 a 9.20.20, 9.21.0 a 9.21.19, y 9.20.9-S1 a 9.20.20-S1.\nLas versiones de BIND 9 9.18.0 a 9.18.46 y 9.18.11-S1 a 9.18.46-S1 NO est\u00e1n afectadas."
    }
  ],
  "id": "CVE-2026-3591",
  "lastModified": "2026-03-25T15:41:33.977",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 5.4,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "LOW",
          "integrityImpact": "LOW",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 2.8,
        "impactScore": 2.5,
        "source": "security-officer@isc.org",
        "type": "Primary"
      }
    ]
  },
  "published": "2026-03-25T14:16:37.297",
  "references": [
    {
      "source": "security-officer@isc.org",
      "url": "https://downloads.isc.org/isc/bind9/9.20.21"
    },
    {
      "source": "security-officer@isc.org",
      "url": "https://downloads.isc.org/isc/bind9/9.21.20"
    },
    {
      "source": "security-officer@isc.org",
      "url": "https://kb.isc.org/docs/cve-2026-3591"
    }
  ],
  "sourceIdentifier": "security-officer@isc.org",
  "vulnStatus": "Awaiting Analysis",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-305"
        },
        {
          "lang": "en",
          "value": "CWE-562"
        }
      ],
      "source": "security-officer@isc.org",
      "type": "Secondary"
    }
  ]
}


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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



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