FKIE_CVE-2026-59728

Vulnerability from fkie_nvd - Published: 2026-07-27 21:17 - Updated: 2026-07-28 16:17
Severity
4.3 (Medium) - CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N
Summary
Astro is a web framework for content-driven websites. In versions 1.0.0 through 4.0.18, the source.title and enclosure.type item fields in packages/astro-rss/src/index.ts are interpolated directly into XML template strings without XML-character escaping before being parsed by fast-xml-parser. Both fields are validated only as z.string(), placing no restriction on XML special characters. An attacker who controls these values can inject arbitrary XML into the generated RSS feed: a value containing " can break out of an attribute (as with enclosure.type), and a value containing </source> can close an element early and inject additional nodes (as with source.title). This corrupts feed structure, injects false metadata (for example, a fake <link> pointing to a malicious URL), and can cause feed readers to misparse or display attacker-controlled content. In SSR mode (output: 'server'), the poisoned feed is served on every request to all subscribers. This issue has been fixed in version 4.0.19.
References
security-advisories@github.comhttps://github.com/withastro/astro/commit/fbcfa039dfe3d700b239f595a6c55ee35e45bd06
security-advisories@github.comhttps://github.com/withastro/astro/pull/17209
security-advisories@github.comhttps://github.com/withastro/astro/releases/tag/@astrojs/rss@4.0.19
security-advisories@github.comhttps://github.com/withastro/astro/security/advisories/GHSA-8j5q-mfj2-5q9q
134c704f-9b21-4f2e-91b3-4a467353bcc0https://github.com/withastro/astro/security/advisories/GHSA-8j5q-mfj2-5q9q
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "product": "astro",
          "vendor": "withastro",
          "versions": [
            {
              "status": "affected",
              "version": "\u003e= 1.0.0, \u003c 4.0.19"
            }
          ]
        }
      ],
      "source": "security-advisories@github.com"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Astro is a web framework for content-driven websites. In versions 1.0.0 through 4.0.18, the source.title and enclosure.type item fields in packages/astro-rss/src/index.ts are interpolated directly into XML template strings without XML-character escaping before being parsed by fast-xml-parser. Both fields are validated only as z.string(), placing no restriction on XML special characters. An attacker who controls these values can inject arbitrary XML into the generated RSS feed: a value containing \" can break out of an attribute (as with enclosure.type), and a value containing \u003c/source\u003e can close an element early and inject additional nodes (as with source.title). This corrupts feed structure, injects false metadata (for example, a fake \u003clink\u003e pointing to a malicious URL), and can cause feed readers to misparse or display attacker-controlled content. In SSR mode (output: \u0027server\u0027), the poisoned feed is served on every request to all subscribers. This issue has been fixed in version 4.0.19."
    }
  ],
  "id": "CVE-2026-59728",
  "lastModified": "2026-07-28T16:17:16.127",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 4.3,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "NONE",
          "integrityImpact": "LOW",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "REQUIRED",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 2.8,
        "impactScore": 1.4,
        "source": "security-advisories@github.com",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-59728",
          "options": [
            {
              "exploitation": "poc"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-07-28T14:27:36.621244Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-07-27T21:17:05.700",
  "references": [
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/withastro/astro/commit/fbcfa039dfe3d700b239f595a6c55ee35e45bd06"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/withastro/astro/pull/17209"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/withastro/astro/releases/tag/@astrojs/rss@4.0.19"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/withastro/astro/security/advisories/GHSA-8j5q-mfj2-5q9q"
    },
    {
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "url": "https://github.com/withastro/astro/security/advisories/GHSA-8j5q-mfj2-5q9q"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Deferred",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-91"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Secondary"
    }
  ]
}



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