Cross-Site Scripting (XSS) in astro (CVE-2026-59729)
Summary
Cross-site scripting in astro (CVE-2026-59729). Risk of unauthorized operations or information disclosure. Exploitable via INVALID_ATTR_NAME_CHAR. Mitigation: upgrade to 7.0.6 or later.
Original description
The description as published by the source.
Astro is a web framework for content-driven websites. Versions prior to 7.0.6 are vulnerable to XSS through unescaped spread attribute names in renderHTMLElement. The fix for CVE-2026-54298 (GHSA-jrpj-wcv7-9fh9) added an INVALID_ATTR_NAME_CHAR guard to addAttribute() so that spread-prop attribute names containing "' >/= or whitespace are dropped. A second attribute-rendering path, renderHTMLElement() in packages/astro/src/runtime/server/render/dom.ts, has its own inline attribute loop that does not go through addAttribute() and was not updated. It interpolates the attribute name unescaped and only escapes the value, so untrusted prop keys spread onto a native-HTMLElement-subclass component can still break out of the attribute context. This issue has been fixed in version 7.0.6.
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-2026-59729 has been found in astro.
Attackers can target a specific entry point like INVALID_ATTR_NAME_CHAR over the network to misuse the product.
Risk of unauthorized operations or information disclosure.
What to do: upgrade astro to 7.0.6 or later.
If unsure, ask your IT team or search "astro CVE-2026-59729" on the vendor's site.
CVE-2026-59729 (astro) — CWE-79
Attack surface: INVALID_ATTR_NAME_CHAR / HTMLElement / renderHTMLElement / attr
Patched: 7.0.6 — 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.
Cross-site scripting (XSS) (CWE-79) exists in astro. Attackers reach the vulnerable code path via INVALID_ATTR_NAME_CHAR.
Check the vendor advisory for the affected versions of astro. Attack surface: INVALID_ATTR_NAME_CHAR / HTMLElement / renderHTMLElement / attr.
Severity: ?. Risk of unauthorized operations or information disclosure.
Update to 7.0.6.
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 'astro' . 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
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1Identify exposure identify
grep -r 'astro' . | 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
astro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 astro to 7.0.6ステージング環境で 7.0.6 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