CVE-2026-64649
SSRF in Next.js Server Actions via attacker-controlled Host header
Is CVE-2026-64649 being exploited?
Not confirmed. CVE-2026-64649 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 0.87% probability of exploitation in the next 30 days.
How severe is CVE-2026-64649?
CVE-2026-64649 is rated High with a CVSS score of 8.3. 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-2026-64649?
Yes. A fix has been recorded for CVE-2026-64649. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-64649 affect?
CVE-2026-64649 affects Next.js 14.1.1 - 15.5.20, Next.js 16.0.0 - 16.2.10, Next.js apps using Server Actions on custom servers, Deployments not behind a host-pinning trusted proxy. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-64649?
Upgrade to Next.js 15.5.21 or 16.2.11; pin host header or deploy behind a trusted proxy.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Server-Side Request Forgery: attacker can force server to make requests to attacker-controlled or internal hosts, potentially accessing internal services or bypassing proxy auth.
Patch when possible
- affected>= 14.1.1 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.