CVE-2025-71389
Unauthenticated RCE in Cal.com via vulnerable Next.js RSC deserialization.
Can a WAF block it? Partly. Code injection payloads are often obfuscated, so they slip past generic WAF rules.
Also consider: remove eval sinks · RASP
Based on the weakness type only; no CVE-specific evidence yet. We check Cloudflare, AWS, Google Cloud Armor and Azure; for Akamai, Imperva, Fastly, F5, ask your vendor.
Is CVE-2025-71389 being exploited?
Not confirmed. CVE-2025-71389 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-2025-71389?
CVE-2025-71389 is rated Critical with a CVSS score of 10.0. 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-2025-71389?
Yes. A fix has been recorded for CVE-2025-71389. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2025-71389 affect?
CVE-2025-71389 affects Cal.com (calcom/cal.diy) versions < 5.9.9, Affected Next.js versions (see CVE-2025-55182). Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2025-71389?
Upgrade Cal.com to >=5.9.9 and update Next.js dependency; isolate/unmonitor affected servers until patched.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Unauthenticated remote code execution via crafted Next.js React Server Components request, allowing arbitrary code execution on the server.
Immediate action required
- affected< 5.9.9
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.