CVE-2026-5749 PUBLISHED

Inadequate access control vulnerability in Fullstep

Assigner: INCIBE
Reserved: 07.04.2026 Published: 22.04.2026 Updated: 22.04.2026

Inadequate access control in the registration process in Fullstep V5, which could allow unauthenticated users to obtain a valid JWT token with which to interact with authenticated API resources. Successful exploitation of this vulnerability could allow an unauthenticated attacker to compromise the confidentiality of the affected resource, provided they have a valid token with which to interact with the API.

Metrics

CVSS 4.0

CVSS Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
CVSS Score: 8.7

Exploitability Metrics		Vulnerable System Impact Metrics		Subsequent System Impact Metrics
Attack Vector	Network	Confidentiality	High	Confidentiality	None
Attack Complexity	Low	Integrity	None	Integrity	None
Attack Requirements	None	Availability	None	Availability	None
Privileges Required	None
User Interaction	None

CVSS 4.0

Product Status

Vendor	Fullstep
Product	Fullstep
Versions	Default: unaffected Version 5 is affected Version 5.30.07 is unaffected

Solutions

The vulnerability has been fixed by the Fullstep team in version 5.30.07, which has been available in production since January 29, 2026.

Credits

Alejandro Rivera León finder

References

https://www.incibe.es/en/incibe-cert/notices/aviso/multiple-vulnerabilities-fullstep

Problem Types

CWE-306 Missing authentication for critical function CWE