CVE-2026-48558
SimpleHelp Authentication Bypass Vulnerability
Does this matter?
Known to be exploited in the wild (CISA KEV, CISA remediation deadline 2 July 2026). Treat as an emergency change: patch or isolate now, then hunt for prior compromise.
Description
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.
- CVSS 4.0
- 9.5 CRITICALCVSS:4.0/AV:N/AC:L/AT:P/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/M
- EPSS
- 64.31% probability · 99th percentile
- CISA KEV
- Listed 29 June 2026 · due 2 July 2026
- Weakness
- CWE-347
- Affected
- simple-help/simplehelp
- Source
- disclosure@vulncheck.com
CISA notes
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. https://simple-help.com/security/simplehelp-security-update-2026-05 ; BOD 26-04: https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk ; Forensics Triage Requirements: https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk ; https://nvd.nist.gov/vuln/detail/CVE-2026-48558
References
- https://horizon3.ai/attack-research/disclosures/cve-2026-48558-simplehelp-authentication-bypass-iocs/Third Party Advisory
- https://simple-help.com/release-newsRelease Notes
- https://simple-help.com/security/simplehelp-security-update-2026-05Patch, Vendor Advisory
- https://blackpointcyber.com/blog/a-djinn-in-the-machine-taskweavers-node-js-intrusion-chain/Technical Description, Third Party Advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-48558US Government Resource
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.