FKIE_CVE-2026-16599

Vulnerability from fkie_nvd - Published: 2026-08-25 15:16 - Updated: 2026-08-28 15:26
Summary
GNU wget is vulnerable to denial of service in its FTP OPIE/S-KEY authentication functionality. The server-supplied sequence number from the FTP challenge line is used as an iteration count for an MD5 key-derivation loop without any upper bound validation. A malicious FTP server or a network attacker positioned to intercept FTP traffic can send a crafted OPIE challenge with a sequence number near INT_MAX, causing wget to perform up to approximately 2.1 billion MD5 computations and suspend for some time. The --timeout option does not mitigate this because it applies only to network I/O, not CPU computation. This issue was fixed in commit e9697d98e7249b0f68a6be040a4f3dcc5bc101fa
Impacted products
Vendor Product Version

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "wget",
          "repo": "https://gitlab.com/gnuwget/wget/",
          "vendor": "GNU",
          "versions": [
            {
              "lessThanOrEqual": "1.25.0",
              "status": "affected",
              "version": "0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "source": "cvd@cert.pl"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "GNU wget is vulnerable to denial of service in its FTP OPIE/S-KEY authentication functionality. The server-supplied sequence number from the FTP challenge line is used as an iteration count for an MD5 key-derivation loop without any upper bound validation. A malicious FTP server or a network attacker positioned to intercept FTP traffic can send a crafted OPIE challenge with a sequence number near INT_MAX, causing wget to perform up to approximately 2.1 billion MD5 computations and suspend for some time. The --timeout option does not mitigate this because it applies only to network I/O, not CPU computation.\n\n\nThis issue was fixed in commit e9697d98e7249b0f68a6be040a4f3dcc5bc101fa"
    }
  ],
  "id": "CVE-2026-16599",
  "lastModified": "2026-08-28T15:26:19.533",
  "metrics": {
    "cvssMetricV40": [
      {
        "cvssData": {
          "Automatable": "NOT_DEFINED",
          "Recovery": "NOT_DEFINED",
          "Safety": "NOT_DEFINED",
          "attackComplexity": "LOW",
          "attackRequirements": "NONE",
          "attackVector": "NETWORK",
          "availabilityRequirement": "NOT_DEFINED",
          "baseScore": 5.1,
          "baseSeverity": "MEDIUM",
          "confidentialityRequirement": "NOT_DEFINED",
          "exploitMaturity": "NOT_DEFINED",
          "integrityRequirement": "NOT_DEFINED",
          "modifiedAttackComplexity": "NOT_DEFINED",
          "modifiedAttackRequirements": "NOT_DEFINED",
          "modifiedAttackVector": "NOT_DEFINED",
          "modifiedPrivilegesRequired": "NOT_DEFINED",
          "modifiedSubAvailabilityImpact": "NOT_DEFINED",
          "modifiedSubConfidentialityImpact": "NOT_DEFINED",
          "modifiedSubIntegrityImpact": "NOT_DEFINED",
          "modifiedUserInteraction": "NOT_DEFINED",
          "modifiedVulnAvailabilityImpact": "NOT_DEFINED",
          "modifiedVulnConfidentialityImpact": "NOT_DEFINED",
          "modifiedVulnIntegrityImpact": "NOT_DEFINED",
          "privilegesRequired": "NONE",
          "providerUrgency": "NOT_DEFINED",
          "subAvailabilityImpact": "NONE",
          "subConfidentialityImpact": "NONE",
          "subIntegrityImpact": "NONE",
          "userInteraction": "ACTIVE",
          "valueDensity": "NOT_DEFINED",
          "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
          "version": "4.0",
          "vulnAvailabilityImpact": "LOW",
          "vulnConfidentialityImpact": "NONE",
          "vulnIntegrityImpact": "NONE",
          "vulnerabilityResponseEffort": "NOT_DEFINED"
        },
        "source": "cvd@cert.pl",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-16599",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-08-25T14:38:32.531936Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-08-25T15:16:30.340",
  "references": [
    {
      "source": "cvd@cert.pl",
      "url": "https://cert.pl/en/posts/2026/08/CVE-2026-16599"
    },
    {
      "source": "cvd@cert.pl",
      "url": "https://gitlab.com/gnuwget/wget"
    },
    {
      "source": "cvd@cert.pl",
      "url": "https://gitlab.com/gnuwget/wget/-/commit/e9697d98e7249b0f68a6be040a4f3dcc5bc101fa"
    }
  ],
  "sourceIdentifier": "cvd@cert.pl",
  "vulnStatus": "Deferred",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-606"
        }
      ],
      "source": "cvd@cert.pl",
      "type": "Primary"
    }
  ]
}



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