CVE-2026-29772

CVE-2026-29772 is a medium-severity vulnerability in Astro @astrojs/node with a CVSS 3.x base score of 5.9. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-770.

Key facts

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.

Frequently asked questions

What is CVE-2026-29772?
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.
How severe is CVE-2026-29772?
CVE-2026-29772 has a CVSS 3.x base score of 5.9, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2026-29772 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (29th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-29772?
CVE-2026-29772 affects Astro @astrojs/node. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-29772?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-29772 have an EU (EUVD) identifier?
Yes. CVE-2026-29772 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-14962.
When was CVE-2026-29772 published?
CVE-2026-29772 was published on 2026-03-24 and last updated on 2026-06-17.

References

Affected products (1)

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