CVE-2026-59728

{"id": "CVE-2026-59728", "cveTags": [], "metrics": {"ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-59728", "role": "CISA Coordinator", "options": [{"exploitation": "poc"}, {"automatable": "no"}, {"technicalImpact": "partial"}], "version": "2.0.3", "timestamp": "2026-07-28T14:27:36.621244Z"}}], "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}]}, "affected": [{"source": "security-advisories@github.com", "affectedData": [{"vendor": "withastro", "product": "astro", "versions": [{"status": "affected", "version": ">= 1.0.0, < 4.0.19"}]}]}], "published": "2026-07-27T21:17:05.700", "references": [{"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": "security-advisories@github.com"}, {"url": "https://github.com/withastro/astro/security/advisories/GHSA-8j5q-mfj2-5q9q", "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0"}], "vulnStatus": "Deferred", "weaknesses": [{"type": "Secondary", "source": "security-advisories@github.com", "description": [{"lang": "en", "value": "CWE-91"}]}], "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 </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."}], "lastModified": "2026-07-28T16:17:16.127", "sourceIdentifier": "security-advisories@github.com"}