SimpleHelp <5.5.16 / 6.0 pre RC2 OIDC Auth Bypass
CVE-2026-48558 Published on June 12, 2026
SimpleHelp Authentication Bypass via Missing OIDC JWT Signature Verification
SimpleHelp versions 5.5.15 and prior and 6.0 pre-release versions contain an authentication bypass vulnerability in the OIDC authentication flow. When OIDC authentication is configured, identity tokens submitted during login are accepted without verifying their cryptographic signature. In a vulnerable configuration, a remote, unauthenticated attacker can submit a forged token containing arbitrary identity claims to obtain a fully authenticated technician session. In some configurations, this may also allow bypass of multi-factor authentication. No user interaction is required.
Known Exploited Vulnerability
This SimpleHelp Authentication Bypass Vulnerability is part of CISA's list of Known Exploited Vulnerabilities. SimpleHelp contains an authentication bypass vulnerability in the OIDC authentication flow. When OIDC authentication is configured, identity tokens submitted during login are accepted without verifying their cryptographic signature. In a vulnerable configuration, a remote, unauthenticated attacker can submit a forged token containing arbitrary identity claims to obtain a fully authenticated technician session. In some configurations, this may also allow bypass of multi-factor authentication.
The following remediation steps are recommended / required by July 2, 2026: Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicab
Vulnerability Analysis
CVE-2026-48558 is exploitable with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. This vulnerability is known to be actively exploited by threat actors in an automatable fashion. The potential impact of an exploit of this vulnerability is considered to be critical as this vulnerability has a high impact to the confidentiality, integrity and availability of this component.
Weakness Type
Improper Verification of Cryptographic Signature
The software does not verify, or incorrectly verifies, the cryptographic signature for data.
Affected Versions
SimpleHelp:- Version 5.5.0 and below 5.5.16 is affected.
- Version 6.0 and below 6.0 RC2 is affected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.