CVE-2026-29772Public exploitNetwork attack vector

Unauthenticated server crash via unbounded JSON parsing

Published Mar 24, 2026 · Updated Mar 24, 2026

Denial of service in Astro before 10.0.0 allows remote attackers to crash Node standalone SSR servers with a crafted POST body. The Server Islands handler calls request.text() and JSON.parse() without a body-size limit, amplifying arrays of small objects into a large V8 heap graph. The route exists on every Astro SSR app using the Node standalone adapter and parses the body before validating the island name, so no authentication or valid name is required.

CVSS severity5.9
Medium
EPSS probability0.37%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Astro before 10.0.0 allows remote attackers to crash Node standalone SSR servers with a crafted POST body. The Server Islands handler calls request.text() and JSON.parse() without a body-size limit, amplifying arrays of small objects into a large V8 heap graph. The route exists on every Astro SSR app using the Node standalone adapter and parses the body before validating the island name, so no authentication or valid name is required.

The record

CVE
CVE-2026-29772
Published
Mar 24, 2026
Updated
Mar 24, 2026
Vendor
Astro
Product
Astro
Classifications
CWE-770, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 24, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 24, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 10.0.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Astro · Astroversion=< 10.0.0

Published CVSS scores

5.9GitHubCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
7.5NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-770Allocation of Resources Without Limits or Throttling
T1499.004Application or System Exploitation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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