MSRXCVE-2026-48558
CVE-2026-48558
SimpleHelp Authentication Bypass via Missing OIDC JWT Signature Verification
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 applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
CVSS 4.0 · CNA
chance of exploitation in the next 30 days (EPSS; in the top 1% of all CVEs)
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.
Scores
Affected products
- SimpleHelp SimpleHelp: 5.5.0 to < 5.5.16; 6.0 to < 6.0 RC2
Weakness: CWE-347
3 references (advisories, patches, write-ups)
- https://horizon3.ai/attack-research/disclosures/cve-2026-48558-simplehelp-authentication-bypass-iocs/ · technical-description, exploit
- https://simple-help.com/security/simplehelp-security-update-2026-05 · vendor-advisory
- https://simple-help.com/release-news · release-notes
Sources: CVE.org, FIRST EPSS. Missing ones did not answer or have no record yet.