CVE-2026-59729
Versions prior to 7.0.6 are vulnerable to XSS through unescaped spread attribute names in renderHTMLElement.
Does this matter?
Lower severity and a low EPSS score (0.32%). Track it; it rarely justifies an emergency change on its own.
Description
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.
- CVSS 4.0
- 5.1 MEDIUMCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
- EPSS
- 0.32% probability · 25th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-79
- Source
- security-advisories@github.com
References
- https://github.com/withastro/astro/commit/5240e26c9dd91f9bc7140dcfacdb48d5a132830d
- https://github.com/withastro/astro/pull/17251
- https://github.com/withastro/astro/releases/tag/astro@7.0.6
- https://github.com/withastro/astro/security/advisories/GHSA-f48w-9m4c-m7f5
- https://github.com/withastro/astro/security/advisories/GHSA-f48w-9m4c-m7f5
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.