CVE-2026-73424: CWE-441: Unintended Proxy or Intermediary ('Confused Deputy') in withastro astro
CVE-2026-73424 is a medium severity vulnerability in the Astro web framework's Vercel adapter versions from 10.0.3 up to but not including 11.0.3. The issue allows unauthenticated GET requests to render routes that are intended to be protected by Vercel edge path rules or split edge middleware. This occurs because the adapter accepts the x_astro_path parameter for the public /_isr function based solely on the x-vercel-isr header, leading to unintended proxy or intermediary behavior (CWE-441). The vulnerability is fixed in version 11.0.3.
AI Analysis
Technical Summary
Astro's Vercel adapter in versions >=10.0.3 and <11.0.3 improperly trusts the x-vercel-isr header to accept the x_astro_path parameter for the public /_isr function. This allows unauthenticated GET requests to bypass intended protections such as Vercel edge path rules or split edge middleware, effectively causing a confused deputy scenario (CWE-441) where the server acts on behalf of an unauthorized request. The vulnerability is addressed in version 11.0.3.
Potential Impact
An attacker can perform unauthenticated GET requests that render routes which should be protected by Vercel edge path rules or middleware. This could lead to unauthorized information disclosure or access to content that relies on edge-level protections. The impact is limited to confidentiality and integrity with no reported availability impact.
Mitigation Recommendations
Upgrade the Astro Vercel adapter to version 11.0.3 or later, where this issue is fixed. No other mitigation is required as the fix is official and addresses the root cause.
CVE-2026-73424: CWE-441: Unintended Proxy or Intermediary ('Confused Deputy') in withastro astro
Description
CVE-2026-73424 is a medium severity vulnerability in the Astro web framework's Vercel adapter versions from 10.0.3 up to but not including 11.0.3. The issue allows unauthenticated GET requests to render routes that are intended to be protected by Vercel edge path rules or split edge middleware. This occurs because the adapter accepts the x_astro_path parameter for the public /_isr function based solely on the x-vercel-isr header, leading to unintended proxy or intermediary behavior (CWE-441). The vulnerability is fixed in version 11.0.3.
CVSS v3.1
Score 6.5medium
Affected software
withastro
astro
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
Astro's Vercel adapter in versions >=10.0.3 and <11.0.3 improperly trusts the x-vercel-isr header to accept the x_astro_path parameter for the public /_isr function. This allows unauthenticated GET requests to bypass intended protections such as Vercel edge path rules or split edge middleware, effectively causing a confused deputy scenario (CWE-441) where the server acts on behalf of an unauthorized request. The vulnerability is addressed in version 11.0.3.
Potential Impact
An attacker can perform unauthenticated GET requests that render routes which should be protected by Vercel edge path rules or middleware. This could lead to unauthorized information disclosure or access to content that relies on edge-level protections. The impact is limited to confidentiality and integrity with no reported availability impact.
Mitigation Recommendations
Upgrade the Astro Vercel adapter to version 11.0.3 or later, where this issue is fixed. No other mitigation is required as the fix is official and addresses the root cause.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-08-12T14:32:11.795Z
- Cvss Version
- 3.1
- State
- PUBLISHED
Threat ID: 6a834478bf8831d5394445cf
Added to database: 08/17/2026, 17:27:20 UTC
Last enriched: 09/12/2026, 01:37:57 UTC
Last updated: 10/01/2026, 14:51:09 UTC
Views: 66
Community Reviews
0 reviewsCrowdsource mitigation strategies, share intel context, and vote on the most helpful responses. Sign in to add your voice and help keep defenders ahead.
Want to contribute mitigation steps or threat intel context? Sign in or create an account to join the community discussion.
Actions
Updates to AI analysis require Pro Console access. Upgrade inside Console → Billing.
Need more coverage?
Upgrade to Pro Console for AI refresh and higher limits.
For incident response and remediation, OffSeq services can help resolve threats faster.
Latest Threats
Check if your credentials are on the dark web
Instant breach scanning across billions of leaked records. Free tier available.