CVE-2026-64641
Next.js Server Actions can be abused to cause CPU exhaustion and block requests.
Is CVE-2026-64641 being exploited?
Not confirmed. CVE-2026-64641 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 1.4% probability of exploitation in the next 30 days.
How severe is CVE-2026-64641?
CVE-2026-64641 is rated High with a CVSS score of 8.2. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-64641?
Yes. A fix has been recorded for CVE-2026-64641. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-64641 affect?
CVE-2026-64641 affects Next.js 13.0.0 - 15.5.20, Next.js 16.0.0 - 16.2.10, Applications using App Router with Server Actions. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-64641?
Upgrade to 15.5.21 or 16.2.11+; disable Server Actions if you cannot patch immediately.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Crafted requests to App Router with Server Actions cause excessive CPU use, enabling denial-of-service by blocking further requests in the same process.
Immediate action required
- affected>= 13.0.0 and < 15.5.21
- affected>= 16.0.0 and < 16.2.11
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.