Astro is a web framework for content-driven websites. In versions 5.2.0 through 5.12.7, there is an Open Redirect vulnerability in the trailing slash redirection logic when handling paths with double slashes. This allows an attacker to redirect users to arbitrary external domains by crafting URLs such as https://mydomain.com//malicious-site.com/. This increases the risk of phishing and other social engineering attacks. This affects sites that use on-demand rendering (SSR) with the Node or Cloudflare adapters. It does not affect static sites, or sites deployed to Netlify or Vercel. This issue is fixed in version 5.12.8. To work around this issue at the network level, block outgoing redirect responses with a Location header value that starts with `//`.
https://github.com/withastro/astro/security/advisories/GHSA-cq8c-xv66-36gw
https://github.com/withastro/astro/commit/0567fb7b50c0c452be387dd7c7264b96bedab48f
Published: 2025-08-08
Updated: 2025-08-08
Base Score: 5.8
Vector: CVSS2#AV:N/AC:M/Au:N/C:P/I:P/A:N
Severity: Medium
Base Score: 6.1
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Severity: Medium
Base Score: 5.5
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N
Severity: Medium
EPSS: 0.00041