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Vulnerability details: VCID-axny-tuav-wyc9
Vulnerability ID VCID-axny-tuav-wyc9
Aliases CVE-2026-29772
GHSA-3rmj-9m5h-8fpv
Summary 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.
Status Published
Exploitability 0.5
Weighted Severity 6.2
Risk 3.1
Affected and Fixed Packages Package Details
Weaknesses (3)
CWE-770 Allocation of Resources Without Limits or Throttling
CWE-937 OWASP Top Ten 2013 Category A9 - Using Components with Known Vulnerabilities
CWE-1035 OWASP Top Ten 2017 Category A9 - Using Components with Known Vulnerabilities
System Score Found at
epss 0.00026 https://api.first.org/data/v1/epss?cve=CVE-2026-29772
epss 0.00026 https://api.first.org/data/v1/epss?cve=CVE-2026-29772
cvssv3.1_qr MODERATE https://github.com/advisories/GHSA-3rmj-9m5h-8fpv
cvssv3.1 5.9 https://github.com/withastro/astro
generic_textual MODERATE https://github.com/withastro/astro
cvssv3.1 5.9 https://github.com/withastro/astro/commit/f9ee8685dd26e9afeba3b48d41ad6714f624b12f
generic_textual MODERATE https://github.com/withastro/astro/commit/f9ee8685dd26e9afeba3b48d41ad6714f624b12f
cvssv3.1 5.9 https://github.com/withastro/astro/releases/tag/@astrojs/node@10.0.0
generic_textual MODERATE https://github.com/withastro/astro/releases/tag/@astrojs/node@10.0.0
cvssv3.1 5.9 https://github.com/withastro/astro/security/advisories/GHSA-3rmj-9m5h-8fpv
cvssv3.1_qr MODERATE https://github.com/withastro/astro/security/advisories/GHSA-3rmj-9m5h-8fpv
generic_textual MODERATE https://github.com/withastro/astro/security/advisories/GHSA-3rmj-9m5h-8fpv
ssvc Track https://github.com/withastro/astro/security/advisories/GHSA-3rmj-9m5h-8fpv
cvssv3.1 5.9 https://nvd.nist.gov/vuln/detail/CVE-2026-29772
generic_textual MODERATE https://nvd.nist.gov/vuln/detail/CVE-2026-29772
Reference id Reference type URL
https://api.first.org/data/v1/epss?cve=CVE-2026-29772
https://github.com/withastro/astro
https://github.com/withastro/astro/commit/f9ee8685dd26e9afeba3b48d41ad6714f624b12f
https://github.com/withastro/astro/releases/tag/@astrojs/node@10.0.0
https://nvd.nist.gov/vuln/detail/CVE-2026-29772
GHSA-3rmj-9m5h-8fpv https://github.com/advisories/GHSA-3rmj-9m5h-8fpv
GHSA-3rmj-9m5h-8fpv https://github.com/withastro/astro/security/advisories/GHSA-3rmj-9m5h-8fpv
No exploits are available.
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H Found at https://github.com/withastro/astro
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

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physical

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Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H Found at https://github.com/withastro/astro/commit/f9ee8685dd26e9afeba3b48d41ad6714f624b12f
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

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Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H Found at https://github.com/withastro/astro/releases/tag/@astrojs/node@10.0.0
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

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Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H Found at https://github.com/withastro/astro/security/advisories/GHSA-3rmj-9m5h-8fpv
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

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none

required

unchanged

changed

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none

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Vector: SSVCv2/E:P/A:N/T:P/P:M/B:A/M:M/D:T/2026-03-24T20:16:28Z/ Found at https://github.com/withastro/astro/security/advisories/GHSA-3rmj-9m5h-8fpv
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H Found at https://nvd.nist.gov/vuln/detail/CVE-2026-29772
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

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low

none
Exploit Prediction Scoring System (EPSS)
Percentile 0.07837
EPSS Score 0.00026
Published At June 11, 2026, 12:55 p.m.
Date Actor Action Source VulnerableCode Version
2026-06-11T16:46:51.981839+00:00 Vulnrichment Import https://github.com/cisagov/vulnrichment/blob/develop/2026/29xxx/CVE-2026-29772.json 38.6.0