CVE-2026-29772
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…
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.39%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
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.
- CVSS 3.1
- 7.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- EPSS
- 0.39% probability · 32th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-770
- Affected
- astro/\@astrojs\/node
- Source
- security-advisories@github.com
EPSS 0.4% since 27 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- https://github.com/withastro/astro/security/advisories/GHSA-3rmj-9m5h-8fpvExploit, Vendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.