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CVE-2026-91972

Status: DeferredHigh (8.7)—

Vikunja versions before 2.6.0 fail to apply rate limiting to /api/v2 public authentication endpoints including login, register, password-reset, and OAuth token routes. Remote unauthenticated attackers can perform unbounded credential guessing, account enumeration, and password-reset flooding attacks without throttling restrictions.

CVSS

Exploitation probability (EPSS)

EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).

🎯 ATT&CK techniques

How this vulnerability is exploited and what the attacker gains, in MITRE ATT&CK terms.

Falta de rate limiting en endpoints públicos de autenticación permite ataques de fuerza bruta sin restricción (T1110) y enumeración de cuentas (T1589.001). Acceso remoto sin autenticación: T1190.

Inferred by our analysis agent from the official description, CVSS vector and CWE, and checked by a supervisor. May contain errors.

🛡️ ATT&CK mitigations that cover these techniques

Vulnerability ScanningUser Account ManagementPrivileged Account ManagementPassword PoliciesNetwork SegmentationMulti-factor Authentication

Affected technologies (1)

⚠ AI-inferred from the description — NVD hasn't analyzed this CVE yet, these aren't verified CPEs.

Vikunja — VikunjaAI

CWEs

References

Raw JSON (NVD)

Show
{
  "id": "CVE-2026-91972",
  "cveTags": [],
  "metrics": {
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      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-91972",
          "role": "CISA Coordinator",
          "options": [
            {
              "exploitation": "poc"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "version": "2.0.3",
          "timestamp": "2026-09-17T15:11:53.582933Z"
        }
      }
    ],
    "cvssMetricV31": [
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        "type": "Secondary",
        "source": "disclosure@vulncheck.com",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 7.5,
          "attackVector": "NETWORK",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N",
          "integrityImpact": "NONE",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "NONE",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 3.6,
        "exploitabilityScore": 3.9
      }
    ],
    "cvssMetricV40": [
      {
        "type": "Secondary",
        "source": "disclosure@vulncheck.com",
        "cvssData": {
          "Safety": "NOT_DEFINED",
          "version": "4.0",
          "Recovery": "NOT_DEFINED",
          "baseScore": 8.7,
          "Automatable": "NOT_DEFINED",
          "attackVector": "NETWORK",
          "baseSeverity": "HIGH",
          "valueDensity": "NOT_DEFINED",
          "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/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",
          "exploitMaturity": "NOT_DEFINED",
          "providerUrgency": "NOT_DEFINED",
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          "privilegesRequired": "NONE",
          "subIntegrityImpact": "NONE",
          "vulnIntegrityImpact": "NONE",
          "integrityRequirement": "NOT_DEFINED",
          "modifiedAttackVector": "NOT_DEFINED",
          "subAvailabilityImpact": "NONE",
          "vulnAvailabilityImpact": "NONE",
          "availabilityRequirement": "NOT_DEFINED",
          "modifiedUserInteraction": "NOT_DEFINED",
          "modifiedAttackComplexity": "NOT_DEFINED",
          "subConfidentialityImpact": "NONE",
          "vulnConfidentialityImpact": "HIGH",
          "confidentialityRequirement": "NOT_DEFINED",
          "modifiedAttackRequirements": "NOT_DEFINED",
          "modifiedPrivilegesRequired": "NOT_DEFINED",
          "modifiedSubIntegrityImpact": "NOT_DEFINED",
          "modifiedVulnIntegrityImpact": "NOT_DEFINED",
          "vulnerabilityResponseEffort": "NOT_DEFINED",
          "modifiedSubAvailabilityImpact": "NOT_DEFINED",
          "modifiedVulnAvailabilityImpact": "NOT_DEFINED",
          "modifiedSubConfidentialityImpact": "NOT_DEFINED",
          "modifiedVulnConfidentialityImpact": "NOT_DEFINED"
        }
      }
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  },
  "affected": [
    {
      "source": "disclosure@vulncheck.com",
      "affectedData": [
        {
          "vendor": "go-vikunja",
          "product": "vikunja",
          "versions": [
            {
              "status": "affected",
              "version": "0",
              "lessThan": "2.6.0",
              "versionType": "semver"
            },
            {
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              "version": "2.6.0",
              "versionType": "semver"
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  ],
  "published": "2026-09-15T16:17:54.087",
  "references": [
    {
      "url": "https://github.com/go-vikunja/vikunja/security/advisories/GHSA-6rvj-qwjf-3m4q",
      "source": "disclosure@vulncheck.com"
    },
    {
      "url": "https://www.vulncheck.com/advisories/vikunja-before-2.6.0-authentication-bypass-via-unthrottled-api",
      "source": "disclosure@vulncheck.com"
    },
    {
      "url": "https://github.com/go-vikunja/vikunja/security/advisories/GHSA-6rvj-qwjf-3m4q",
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0"
    }
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  "vulnStatus": "Deferred",
  "weaknesses": [
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      "type": "Secondary",
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      "description": [
        {
          "lang": "en",
          "value": "CWE-307"
        }
      ]
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  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "Vikunja versions before 2.6.0 fail to apply rate limiting to /api/v2 public authentication endpoints including login, register, password-reset, and OAuth token routes. Remote unauthenticated attackers can perform unbounded credential guessing, account enumeration, and password-reset flooding attacks without throttling restrictions."
    }
  ],
  "lastModified": "2026-09-17T16:18:32.093",
  "sourceIdentifier": "disclosure@vulncheck.com"
}