CVE-2025-71389: Code Injection (CVSS 10)

Description

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 vulnerability CVE-2025-55182 and is resolved in 5.9.9 by updating the affected dependency.

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CVSS v3.1 Score

10.0

CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

EPSS — Exploit Prediction

0.0093

Probability of exploitation

0.57%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-94 CWE-94

References

Other References

https://github.com/advisories/GHSA-9qr9-h5gf-34mp https://github.com/calcom/cal.diy/pull/25592 https://github.com/calcom/cal.diy/security/advisories/GHSA-qjx2-5xqp-cpf4 https://www.vulncheck.com/advisories/cal-com-before-remote-code-execution-via-rsc

Frequently Asked Questions

What is CVE-2025-71389? +

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 vulnerability CVE-2025-55182 and is resolved in 5.9.9 by updating the affected dependency. It has a CVSS v3.1 base score of 10.0 (CRITICAL).

How severe is CVE-2025-71389? +

CVE-2025-71389 has a CVSS v3.1 score of 10.0 out of 10, rated CRITICAL. This is a critical vulnerability that should be patched immediately. The EPSS score is 0.0093, placing it in the 1th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2025-71389? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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