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CVE-2026-29772

HIGH CVSS 3.1: 7.5 EPSS 0.01%
Updated Mar 25, 2026
Payload
Parameter Value
CVSS 7.5 (HIGH)
Affected Versions 9.0.0 — 10.0.0
Fixed In 10.0.0
Type CWE-770 (Allocation Without Limits)
Vendor Payload
Public PoC No

Astro is a web framework. Prior to version 10.0.0, Astro's Server Islands POST handler buffers and parses the full request body as JSON without enforcing a size limit. Because JSON.parse() allocates a V8 heap object for every element in the input, a crafted payload of many small JSON objects achieves ~15x memory amplification (wire bytes to heap bytes), allowing a single unauthenticated request to exhaust the process heap and crash the server.

The /_server-islands/[name] route is registered on all Astro SSR apps regardless of whether any component uses server:defer, and the body is parsed before the island name is validated, so any Astro SSR app with the Node standalone adapter is affected. This issue has been patched in version 10.0.0.

Attack Parameters

Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Privileges Required
None
No privileges needed
User Interaction
None
No user interaction needed

Impact Assessment

Confidentiality
None
No data leak
Integrity
None
No data modification
Availability
High
Complete denial of service

CVSS Vector v3.1

Vulnerable Products 1

Configuration From (including) Up to (excluding)
Astro \@Astrojs\/Node
cpe:2.3:a:astro:\@astrojs\/node:*:*:*:*:*:node.js:*:*
9.0.0 10.0.0