How severe is CVE-2026-59730?

No CVSS score has been assigned to CVE-2026-59730 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-59730?

CVE-2026-59730 affects the following packages: @astrojs/node (npm). Ecosystems affected: npm.

How do I fix CVE-2026-59730?

Update @astrojs/node to 11.0.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-59730 is resolved across your whole dependency graph.

How do I detect CVE-2026-59730 in my npm dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @astrojs/node, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2026-59730 if there is no patch (or I can't update yet)?

Stop reflecting attacker-controlled destinations: resolve every redirect target against an allowlist of paths or hosts you own, prefer a server-side key over a full URL in the request, and reject absolute URLs entirely where the flow only ever needs a relative one.

Is CVE-2026-59730 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-59730 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 CVE-2026-59730?

CVE-2026-59730 has an EPSS (Exploit Prediction Scoring System) score of 0.5%, placing it in the 39th 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.

What type of vulnerability is CVE-2026-59730?

CVE-2026-59730 is classified as Open Redirect (CWE-601). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2026-59730 published, and has it been updated?

CVE-2026-59730 was published on July 27, 2026 and was last updated on October 21, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

📦 npm

Not in CISA KEV

CVE-2026-59730 — @astrojs/node

Fix: withastro/astro@eb6f97e

CVE-2026-59730 is a Open Redirect vulnerability in @astrojs/node. A fix is available for @astrojs/node — see the affected versions and patch details below.

@astrojs/node: Backslash-prefixed paths not recognized as internal by trailing-slash redirect

Also known asGHSA-r557-wffq-wvrc

Published

Jul 27, 2026

Updated

Oct 21, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Oct 21, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-59730.

EPSS Exploitation Probability

via FIRST.org ↗

0.5%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs39th percentile — riskier than 39% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

1 pkg affected

How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.

92other npm packages depend on this — each one inherits the vulnerability until it's patched upstream

@astrojs/nodenpm

577Kdownloads / week

Description

Impact

With trailingSlash: 'always' configured, the @astrojs/node standalone server's static file handler appends a trailing slash to request paths and issues a 301 redirect. Paths beginning with /\ (slash-backslash) were not recognized as internal paths, so the handler would echo the raw path back in the Location header. Because browsers treat \ as / per the WHATWG URL specification, the resulting redirect could resolve to an external host.

Preconditions:

trailingSlash: 'always' must be set (non-default; the default is 'ignore')
The request path must not have a file extension in its final segment
An attacker must deliver the crafted link to a user

Patches

Fixed by treating backslash-prefixed paths the same as //-prefixed paths in isInternalPath(), so they are no longer rewritten with a trailing slash.

Workarounds

Use the default trailingSlash: 'ignore' setting, which does not issue trailing-slash redirects in the static file handler.

References

WHATWG URL spec: backslash normalization

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`@astrojs/node`	≥ 8.1.0&&< 11.0.2	11.0.2`npm install @astrojs/node@11.0.2`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @astrojs/node, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update @astrojs/node to 11.0.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-59730 is resolved across your whole dependency graph.
Workarounds
Stop reflecting attacker-controlled destinations: resolve every redirect target against an allowlist of paths or hosts you own, prefer a server-side key over a full URL in the request, and reject absolute URLs entirely where the flow only ever needs a relative one.

Frequently Asked Questions

### Impact With `trailingSlash: 'always'` configured, the `@astrojs/node` standalone server's static file handler appends a trailing slash to request paths and issues a `301` redirect. Paths beginning with `/\` (slash-backslash) were not recognized as internal paths, so the handler would echo the raw path back in the `Location` header. Because browsers treat `\` as `/` per the WHATWG URL specification, the resulting redirect could resolve to an external host. **Preconditions:** - `trailingSlash: 'always'` must be set (non-default; the default is `'ignore'`) - The request path must not have a

O3 Security · Impact-Aware SCA

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