CVE-2026-59731: Astro: Authorization Bypass via Decode Iteration Limit and Rewrite Path Canonicalization…

Astro 6.4.7 Authorization Bypass via Decode Iteration Limit and Rewrite Path Canonicalization Mismatch Summary Astro 6.4.7 appears to reintroduce a middleware authorization bypass pattern when a request path is encoded…

8.2CVSS Score

HIGHSeverity

NOCISA KEV

0.3%EPSS Score

VulnerabilityImpact Type

📋 Vulnerability Details

CVE ID	CVE-2026-59731
Vendor	npm
Affected Product	astro
Vulnerability Type	Vulnerability
CVSS Score	8.2 (HIGH)
EPSS Score	0.3% probability of exploitation in the next 30 days
Actively Exploited	❌ No known exploitation
Patch Status	See Vendor Advisory →
Reported By	CYBERDUDEBIVASH SENTINEL APEX Intelligence (via github_advisories)

🔬 Technical Analysis

Astro 6.4.7 Authorization Bypass via Decode Iteration Limit and Rewrite Path Canonicalization Mismatch

Summary Astro 6.4.7 appears to reintroduce a middleware authorization bypass pattern when a request path is encoded more deeply than the newly introduced iterative URL decoder's maximum decoding depth. The issue occurs because Astro performs authorization decisions on a partially decoded pathname after reaching a decoding iteration cap, while later route matching logic performs an additional `decodeURI()` operation and resolves the request to a protected route. As a result, middleware and route matching may operate on different pathname representations, enabling authorization bypasses under specific application patterns. Potential CWE: CWE-647 – Use of Non-Canonical URL Paths for

📚 Advisory References

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