CVE-2026-59727
If a developer reflects attacker-controlled input into one of these directives, an attacker can break out of the attribute and inject arbitrary HTML/JavaScript into the server-rendered output, resulting in reflected cross-site scripting (XSS).
Does this matter?
Lower severity and a low EPSS score (0.31%). Track it; it rarely justifies an emergency change on its own.
Description
Astro is a web framework for content-driven websites. In versions 3.10.0 through 7.0.3, when a transition:persist, transition:scope, or transition:persist-props directive is applied to a client-hydrated (client:*) component, Astro copied the directive value onto the rendered <astro-island> element without HTML-escaping it. If a developer reflects attacker-controlled input into one of these directives, an attacker can break out of the attribute and inject arbitrary HTML/JavaScript into the server-rendered output, resulting in reflected cross-site scripting (XSS). Exploitation requires the application developer to have written a non-idiomatic pattern — passing untrusted, request-derived input directly into a transition directive. Astro applications that do not route untrusted input into these directives are unaffected. This issue has been fixed in version 7.0.4.
- CVSS 4.0
- 2.1 LOWCVSS:4.0/AV:N/AC:L/AT:P/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
- 0.31% probability · 24th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-79, CWE-83, CWE-116
- Source
- security-advisories@github.com
References
- https://github.com/withastro/astro/commit/7ba0bb1dc7516e88caff9abd7767322af44b0294
- https://github.com/withastro/astro/pull/17212
- https://github.com/withastro/astro/releases/tag/astro@7.0.4
- https://github.com/withastro/astro/security/advisories/GHSA-7pw4-f3q4-r2p2
- https://github.com/withastro/astro/security/advisories/GHSA-7pw4-f3q4-r2p2
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.