Is CVE-2026-59731 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-59731 being exploited in the wild.

How severe is CVE-2026-59731?

High severity, with a CVSS score of 8.2, published 8 July 2026.

Which products and versions are affected?

astro (npm) >= 6.4.7, < 6.4.8, SEMVER:introduced=6.4.7,fixed=6.4.8.

Is there a fix for CVE-2026-59731?

Yes. astro (npm): upgrade to 6.4.8 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-59731 attacked?

It is attacked over the network, in a software library.

Am I affected by CVE-2026-59731?

Check whether you run astro (npm) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-59731: withastro Astro authorization bypass via URL decoding mismatch

Q: Is there a fix for CVE-2026-59731?

Yes. astro (npm): upgrade to 6.4.8 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

Q: How is CVE-2026-59731 attacked?

It is attacked over the network, in a software library.

Q: Am I affected by CVE-2026-59731?

Check whether you run astro (npm) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-59731 · Severity: high · CVSS 8.2 · Published 2026-07-08

Astro is a popular web framework used to build fast websites. A security flaw in how it handles web addresses (URLs) allows attackers to bypass security rules that protect sensitive areas like admin dashboards or private APIs. By specially crafting a URL with many layers of encoding, an attacker can trick the security system into thinking the request is safe while the internal router still sends them to a protected page.

Technologies: astro (npm). Vendors: npm.

Quick answers

Is CVE-2026-59731 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-59731 being exploited in the wild.
How severe is CVE-2026-59731?: High severity, with a CVSS score of 8.2, published 8 July 2026.
Which products and versions are affected?: astro (npm) >= 6.4.7, < 6.4.8, SEMVER:introduced=6.4.7,fixed=6.4.8.
Is there a fix for CVE-2026-59731?: Yes. astro (npm): upgrade to 6.4.8 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-59731 attacked?: It is attacked over the network, in a software library.
Am I affected by CVE-2026-59731?: Check whether you run astro (npm) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

astro (npm): upgrade to 6.4.8 or later
```
npm install astro@6.4.8
```

Technical details

Astro 6.4.7 introduced iterative URI decoding with a maximum cap of 10 iterations. If a URL is encoded more than 10 times (e.g., depth 11), the middleware receives a partially decoded string, while the subsequent route matching logic performs an additional decodeURI() call. This canonicalization mismatch (CWE-647) allows an attacker to bypass path-based authorization checks in middleware and reach protected routes. The vulnerability is exploitable when applications use path-based authorization and rewrite-based routing (next(context.url)). The issue is resolved in version 6.4.8 by rejecting requests that exceed the decoding iteration limit.

Affected products

withastro Astro >= 6.4.7, < 6.4.8

Identifiers

CVE-2026-59731
GHSA-vj59-8hwv-xxmv

Timeline

2026-07-01: disclosed
2026-07-01: patched: Fixed in version 6.4.8
2026-07-20: advisory

References

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