@astrojs/rss: XML Injection via Unescaped RSS Feed Fields

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-59728
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-07-27 21:17:05 UTC
Updated2026-07-28 15:17:20 UTC
DescriptionAstro 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.

Risk And Classification

Primary CVSS: v3.1 4.3 MEDIUM from [email protected]

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

Problem Types: CWE-91 | CWE-91 CWE-91: XML Injection (aka Blind XPath Injection)

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary4.3MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N
3.1CNADECLARED4.3MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
Required
Scope
Unchanged
Confidentiality
None
Integrity
Low
Availability
None

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Withastro Astro affected >= 1.0.0, < 4.0.19 Not specified

References

ReferenceSourceLinkTags
github.com/withastro/astro/commit/fbcfa039dfe3d700b239f595a6c55ee35e45bd06 [email protected] github.com
github.com/withastro/astro/releases/tag/@astrojs/[email protected] [email protected] github.com
github.com/withastro/astro/security/advisories/GHSA-8j5q-mfj2-5q9q 134c704f-9b21-4f2e-91b3-4a467353bcc0 github.com
github.com/withastro/astro/pull/17209 [email protected] github.com
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NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

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