PatchTheCVECVE-2025-71389: Cal.com (calcom/cal.diy) before 5.9.9 is vulnerable to unauthenticated remote code execution because it bundle
CVE-2025-71389 is a critical-severity flaw (CVSS 10.0) affecting affected software. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
Cal.com (calcom/cal.diy) before 5.9.9 is vulnerable to unauthenticated remote code execution because it bundles a version of Next.js whose React Server Components (RSC) request handling deserializes attacker-controlled input. A remote attacker can send a crafted RSC request to the server and cause arbitrary code to be executed during server-side processing, without authentication or user interaction. The flaw derives from the upstream Next.js vul
Why this priority
- Critical severity
- CISA SSVC: automatable with total technical impact
- Remotely exploitable, no login, no user action
A fixed release or distro patch exists.
Risk facts
| CVSS score | 10.0 (Critical) |
| Attack vector | Network (remote) |
| Attack complexity | Low |
| Privileges needed | None |
| User interaction | None |
| EPSS exploit chance | 1.4% (top 29%) |
| CISA exploited list | No |
| Weakness | CWE-94 |
| Published | 2026-07-23 |
| Last modified | 2026-09-29 |
Last updated 2026-09-29 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Timeline
- Published CVE record published
- Updated Record last modified
Exact fixes by distribution
Public exploits and detection
Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.
- GitHub PoC: 0xdak/CVE-2025-71389_exploit (0 stars)
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Quick answers
How do I fix CVE-2025-71389?
No fixed release is listed yet. Watch the vendor advisory and apply any mitigation shown on this page.
Is CVE-2025-71389 being exploited?
CVE-2025-71389 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.
What does CVE-2025-71389 affect?
CVE-2025-71389 affects affected software. Severity is critical (CVSS 10.0). Cal.com (calcom/cal.diy) before 5.9.9 is vulnerable to unauthenticated remote code execution because it bundles a version of Next.js whose React Server Components (RSC) request handling deserializes attacker-controlled input. A remote attac
How urgent is CVE-2025-71389?
Priority 61/100. Critical severity; CISA SSVC: automatable with total technical impact; Remotely exploitable, no login, no user action
Software pages
React vulnerabilities · Next.js vulnerabilities