---
cve: "CVE-2026-59728"
severity: "MEDIUM"
cvss: 4.3
epss: "27%"
vendor: "withastro"
kev: false
exploited: false
published: "2026-07-27 21:17:05"
tags: [cve, security, medium]
source: tsecurity.de CVE-Dossier
exported: "2026-09-16T21:26:53+02:00"
---

# CVE-2026-59728

> 4.3 MEDIUM · 🧪 PoC

## Beschreibung

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  can close an element early and inject additional nodes (as with source.title). This corrupts feed structure, injects false metadata (for example, a fake  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.

## CVSS-Vektor

```
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Gering | bad |
| PR Privilegien | Keine | bad |
| UI Interaktion | Erforderlich | good |
| S Scope | Unverändert | good |
| C Vertraulichkeit | Keine | good |
| I Integrität | Gering | warn |
| A Verfügbarkeit | Keine | good |

## Patch verfügbar (OSV)

- 5978993531ba3f02a4c639d223f810e80a1fa7d3 (Commit)

## Referenzen

- <https://github.com/withastro/astro/security/advisories/GHSA-8j5q-mfj2-5q9q>
- <https://github.com/withastro/astro/pull/17209>
- <https://github.com/withastro/astro/commit/fbcfa039dfe3d700b239f595a6c55ee35e45bd06>
- <https://github.com/withastro/astro/releases/tag/@astrojs/rss@4.0.19>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-59728) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_