Cal.com before 5.9.9 Remote Code Execution via RSC

Summary

CVECVE-2025-71389
StatePUBLISHED
AssignerVulnCheck
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-07-23 22:16:51 UTC
Updated2026-07-30 16:41:25 UTC
DescriptionCal.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.

Risk And Classification

Primary CVSS: v4.0 10 CRITICAL from [email protected]

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS: 0.009280000 probability, percentile 0.570520000 (date 2026-08-03)

Problem Types: CWE-94 | CWE-94 Improper Control of Generation of Code ('Code Injection')


VersionSourceTypeScoreSeverityVector
4.0[email protected]Secondary10CRITICALCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/C...
4.0CNACVSS10CRITICALCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
3.1[email protected]Secondary10CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
3.1CNACVSS10CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

CVSS v4.0 Breakdown

Attack Vector
Network
Attack Complexity
Low
Attack Requirements
None
Privileges Required
None
User Interaction
None
Confidentiality
High
Integrity
High
Availability
High
Sub Conf.
High
Sub Integrity
High
Sub Availability
High

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Calcom Cal.diy affected 5.9.9 semver Not specified
CNA Calcom Cal.diy unaffected 5.9.9 semver Not specified

References

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