How severe is GHSA-cq8c-xv66-36gw?

No CVSS score has been assigned to GHSA-cq8c-xv66-36gw yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by GHSA-cq8c-xv66-36gw?

GHSA-cq8c-xv66-36gw affects the following packages: astro (npm). Ecosystems affected: npm.

How do I fix GHSA-cq8c-xv66-36gw?

Update astro to 5.12.8 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-cq8c-xv66-36gw is resolved across your whole dependency graph.

How do I detect GHSA-cq8c-xv66-36gw in my npm dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for astro. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

How do I mitigate GHSA-cq8c-xv66-36gw if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How does O3 Security protect against GHSA-cq8c-xv66-36gw?

O3 pinpoints whether GHSA-cq8c-xv66-36gw is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is GHSA-cq8c-xv66-36gw actively exploited in the wild?

No public exploit code has been indexed for GHSA-cq8c-xv66-36gw yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for GHSA-cq8c-xv66-36gw?

GHSA-cq8c-xv66-36gw has an EPSS (Exploit Prediction Scoring System) score of 0.6%, placing it in the 43th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

Is there exploit tooling available for GHSA-cq8c-xv66-36gw?

A Nuclei detection template exists for GHSA-cq8c-xv66-36gw, meaning automated scanners can fingerprint it. Public exploit tooling significantly increases real-world risk — prioritize patching and ensure detection coverage. Exploit tooling should only ever be used in isolated, authorized testing environments.

When was GHSA-cq8c-xv66-36gw published, and has it been updated?

GHSA-cq8c-xv66-36gw was published on August 7, 2025 and was last updated on November 27, 2025. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

📦 npm

GHSA-cq8c-xv66-36gw

Astros's duplicate trailing slash feature leads to an open redirection security issue

Also known asCVE-2025-54793

Published

Aug 7, 2025

Updated

Nov 27, 2025

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

EPSS Exploitation Probability

via FIRST.org ↗

0.6%probability of exploitation in next 30 days

Lower Risk43th percentile-0.07%

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Blast Radius

1 pkg affected

Weekly download volume for affected packages — a proxy for how broadly this vulnerability is deployed.

astronpm

3.6Mdownloads / week

Description

Summary

There is an Open Redirection 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 Astro >=5.2.0 sites that use on-demand rendering (SSR) with the Node or Cloudflare adapter. It does not affect static sites, or sites deployed to Netlify or Vercel.

Background

Astro performs automatic redirection to the canonical URL, either adding or removing trailing slashes according to the value of the trailingSlash configuration option. It follows the following rules:

If trailingSlash is set to "never", https://example.com/page/ will redirect to https://example.com/page
If trailingSlash is set to "always", https://example.com/page will redirect to https://example.com/page/

It also collapses multiple trailing slashes, according to the following rules:

If trailingSlash is set to "always" or "ignore" (the default), https://example.com/page// will redirect to https://example.com/page/
If trailingSlash is set to "never", https://example.com/page// will redirect to https://example.com/page

It does this by returning a 301 redirect to the target path. The vulnerability occurs because it uses a relative path for the redirect. To redirect from https://example.com/page to https://example.com/page/, it sending a 301 response with the header Location: /page/. The browser resolves this URL relative to the original page URL and redirects to https://example.com/page/

Details

The vulnerability occurs if the target path starts with //. A request for https://example.com//page will send the header Location: //page/. The browser interprets this as a protocol-relative URL, so instead of redirecting to https://example.com//page/, it will attempt to redirect to https://page/. This is unlikely to resolve, but by crafting a URL in the form https://example.com//target.domain/subpath, it will send the header Location: //target.domain/subpath/, which the browser translates as a redirect to https://target.domain/subpath/. The subpath part is required because otherwise Astro will interpret /target.domain as a file download, which skips trailing slash handling.

This leads to an Open Redirect vulnerability.

The URL needed to trigger the vulnerability varies according to the trailingSlash setting.

If trailingSlash is set to "never", a URL in the form https://example.com//target.domain/subpath/
If trailingSlash is set to "always", a URL in the form https://example.com//target.domain/subpath
For any config value, a URL in the form https://example.com//target.domain/subpath//

Impact

This is classified as an Open Redirection vulnerability (CWE-601). It affects any user who clicks on a specially crafted link pointing to the affected domain. Since the domain appears legitimate, victims may be tricked into trusting the redirected page, leading to possible credential theft, malware distribution, or other phishing-related attacks.

No authentication is required to exploit this vulnerability. Any unauthenticated user can trigger the redirect by clicking a malicious link.

Mitigation

Usrs can test if your site is affected by visiting https://yoursite.com//docs.astro.build/en//. If a user is redirected to the Astro docs then their site is affected and must be updated.

Upgrade to Astro 5.12.8. To mitigate at the network level, block outgoing redirect responses with a Location header value that starts with //.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`astro`	≥ 5.2.0&&< 5.12.8	5.12.8

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for astro. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update astro to 5.12.8 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-cq8c-xv66-36gw is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-cq8c-xv66-36gw is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to GHSA-cq8c-xv66-36gw. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

## Summary There is an Open Redirection 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 Astro >=5.2.0 sites that use on-demand rendering (SSR) with the Node or Cloudflare adapter. It does not affect static sites, or sites deployed to Netlify or Vercel. ## Background Astro performs automatic redirection to the canonical

O3 Security · Impact-Aware SCA

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