CVE-2026-71321

CVE-2026-71321 is a high-severity vulnerability with a CVSS 3.x base score of 7.5. 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-407.

Key facts

Description

Nuxt is an open-source web development framework for Vue.js. From 3.1.0 until 3.21.10 and 4.5.1, the internal island renderer endpoint `/__nuxt_island/...` decodes and hashes attacker-controlled JSON body input with destr and ohash before validating the URL-resident hash. An unauthenticated `POST /__nuxt_island/_.json` with a large JSON body is fully read, parsed, hashed, and then rejected, which wastes CPU on Nitro single event loop and delays concurrent requests. No valid hash and no authentication are required. This issue is fixed in 3.21.10 and 4.5.1.

Frequently asked questions

What is CVE-2026-71321?
Nuxt is an open-source web development framework for Vue.js. From 3.1.0 until 3.21.10 and 4.5.1, the internal island renderer endpoint `/__nuxt_island/...` decodes and hashes attacker-controlled JSON body input with destr and ohash before validating the URL-resident hash. An unauthenticated `POST /__nuxt_island/_.json` with a large JSON body is fully read, parsed, hashed, and then rejected, which wastes CPU on Nitro single event loop and delays concurrent requests. No valid hash and no authentication are required. This issue is fixed in 3.21.10 and 4.5.1.
How severe is CVE-2026-71321?
CVE-2026-71321 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2026-71321 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (36th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-71321?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2026-71321 published?
CVE-2026-71321 was published on 2026-08-05 and last updated on 2026-08-06.

References

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