CVE-2026-126362

Description

Astro is a web framework for content-driven websites. From 5.7.3 until 9.1.2, the @astrojs/svelte renderer inserted a named slot into the quoted name attribute of an astro-slot wrapper without HTML escaping. Request-controlled slot names containing a quote could terminate the attribute and inject active HTML. Exploitation required a hydrated Svelte component using a client:* directive and dynamic rendering of the attacker-chosen slot; components that did not render that slot emitted only Astro's escaped fallback content. Both server rendering and client-side hydration used the unsafe slot name. This issue is fixed in version 9.1.2.

Severity scores

Each score is shown as its source gave it. They are not averaged or merged.

• 2.3CVSS 4.0, Lowfrom the CNA (GitHub_M)CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N

Historical context and remediation

This reference retains the original CVE publication date. A recent record update does not mean a new attack occurred.

No separately sourced impact summary is available on this page yet. Consult the description, version data and dated exploitation evidence.

No explicit remediation statement is available on this page yet. Consult the original record and vendor references before choosing a fix.

Version statuses below come from the CNA. An “unaffected” version is not necessarily a currently supported release or proof of a patch date. EPSS is a dated risk estimate, not a count of historical attacks.

Read the original CVE record.

Affected products

Timeline

1. 12 Nov 2026 Published

Weakness

• CWE-79

References

• https://github.com/withastro/astro/security/advisories/GHSA-f4j9-crrj-867qx_refsource_CONFIRM
• https://github.com/withastro/astro/commit/5e476365378e41aa2745d003b2383d02008d7b44x_refsource_MISC
• https://github.com/withastro/astro/releases/tag/@astrojs/svelte@9.1.2x_refsource_MISC