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CVE-2025-62595

Status: AnalyzedMedium (6.1)—

Koa is expressive middleware for Node.js using ES2017 async functions. In versions 2.16.2 to before 2.16.3 and 3.0.1 to before 3.0.3, a bypass to CVE-2025-8129 was discovered in the Koa.js framework affecting its back redirect functionality. In certain circumstances, an attacker can manipulate the Referer header to force a user’s browser to navigate to an external, potentially malicious website. This occurs because the implementation incorrectly treats some specially crafted URLs as safe relative paths. Exploiting this vulnerability could allow attackers to perform phishing, social engineering, or other redirect-based attacks on users of affected applications. This issue has been patched in version 3.0.3.

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).

Affected technologies (1)

Koajs — KOA

CWEs

References

Raw JSON (NVD)

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{
  "id": "CVE-2025-62595",
  "cveTags": [],
  "metrics": {
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2025-62595",
          "role": "CISA Coordinator",
          "options": [
            {
              "exploitation": "poc"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "version": "2.0.3",
          "timestamp": "2025-10-21T16:35:45.437787Z"
        }
      }
    ],
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "security-advisories@github.com",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 4.3,
          "attackVector": "NETWORK",
          "baseSeverity": "MEDIUM",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N",
          "integrityImpact": "LOW",
          "userInteraction": "REQUIRED",
          "attackComplexity": "LOW",
          "availabilityImpact": "NONE",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "NONE"
        },
        "impactScore": 1.4,
        "exploitabilityScore": 2.8
      },
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "scope": "CHANGED",
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          "attackVector": "NETWORK",
          "baseSeverity": "MEDIUM",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N",
          "integrityImpact": "LOW",
          "userInteraction": "REQUIRED",
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          "privilegesRequired": "NONE",
          "confidentialityImpact": "LOW"
        },
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      }
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  },
  "affected": [
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      "source": "security-advisories@github.com",
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              "version": ">= 2.16.2, < 2.16.3"
            },
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              "version": ">= 3.0.1, < 3.0.3"
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  "published": "2025-10-21T17:15:40.737",
  "references": [
    {
      "url": "https://github.com/koajs/koa/commit/769fd75cc6b30d72493b370b5a3ae2332ca03c5b",
      "tags": [
        "Patch"
      ],
      "source": "security-advisories@github.com"
    },
    {
      "url": "https://github.com/koajs/koa/security/advisories/GHSA-g8mr-fgfg-5qpc",
      "tags": [
        "Exploit",
        "Vendor Advisory"
      ],
      "source": "security-advisories@github.com"
    },
    {
      "url": "https://github.com/koajs/koa/security/advisories/GHSA-g8mr-fgfg-5qpc",
      "tags": [
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        "Vendor Advisory"
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      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0"
    }
  ],
  "vulnStatus": "Analyzed",
  "weaknesses": [
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      "type": "Secondary",
      "source": "security-advisories@github.com",
      "description": [
        {
          "lang": "en",
          "value": "CWE-601"
        }
      ]
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  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "Koa is expressive middleware for Node.js using ES2017 async functions. In versions 2.16.2 to before 2.16.3 and 3.0.1 to before 3.0.3, a bypass to CVE-2025-8129 was discovered in the Koa.js framework affecting its back redirect functionality. In certain circumstances, an attacker can manipulate the Referer header to force a user’s browser to navigate to an external, potentially malicious website. This occurs because the implementation incorrectly treats some specially crafted URLs as safe relative paths. Exploiting this vulnerability could allow attackers to perform phishing, social engineering, or other redirect-based attacks on users of affected applications. This issue has been patched in version 3.0.3."
    }
  ],
  "lastModified": "2026-06-17T09:52:07.903",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:koajs:koa:*:*:*:*:*:node.js:*:*",
              "vulnerable": true,
              "matchCriteriaId": "4A627ED5-2951-46B1-BFF3-E633EE820936",
              "versionEndExcluding": "3.0.3",
              "versionStartIncluding": "3.0.1"
            },
            {
              "criteria": "cpe:2.3:a:koajs:koa:2.16.2:*:*:*:*:node.js:*:*",
              "vulnerable": true,
              "matchCriteriaId": "23C668B2-3773-49E0-9274-7C8824F59CB0"
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          "operator": "OR"
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  "sourceIdentifier": "security-advisories@github.com"
}