Vulnerability in @astrojs/rss (CVE-2026-59728)
Summary
Vulnerability in @astrojs/rss (CVE-2026-59728). Risk of unauthorized operations or information disclosure. Exploitable via source.title. Mitigation: upgrade to 4.0.19 or later.
Original description
The description as published by the source.
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.
Source: GitHub Security Advisories (Global) NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-59728 has been found in @astrojs/rss.
Attackers can target a specific entry point like source.title over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 4.3/10.
What to do: upgrade @astrojs/rss to 4.0.19 or later.
If unsure, ask your IT team or search "@astrojs/rss CVE-2026-59728" on the vendor's site.
CVE-2026-59728 (@astrojs/rss) — CWE-91 / CVSS v3 4.3
Attack vector: remote (network-reachable) / unauthenticated
Attack surface: source.title / enclosure.type / RSSFeedItem
Patched: 4.0.19 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (CWE-91) exists in @astrojs/rss. Attackers reach the vulnerable code path via source.title without authentication.
Check the vendor advisory for the affected versions of @astrojs/rss. Attack surface: source.title / enclosure.type / RSSFeedItem.
Severity: Medium (CVSS 4.3/10). Risk of unauthorized operations or information disclosure.
Update to 4.0.19.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r '@astrojs/rss' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r '@astrojs/rss' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
@astrojs/rssを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply patch patch
Upgrade @astrojs/rss to 4.0.19ステージング環境で 4.0.19 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
-
3Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
References
- advisory github.com
- advisory nvd.nist.gov
- advisory github.com
- package github.com
- patch github.com
- patch github.com
- web github.com
- web github.com