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Critical

Authentication Bypass in SimpleHelp OIDC Authentication Flow

IdentifiersCVE-2026-48558CWE-347· Improper Verification of…

CVE-2026-48558 is a critical authentication bypass vulnerability affecting SimpleHelp versions 5.5.15 and earlier, as well as 6.0 pre-release versions. The flaw exists in the OpenID Connect (OIDC) authentication flow: when OIDC authentication is configured, SimpleHelp accepts submitted identity tokens during login without verifying their cryptographic signature. Because the token signature is not validated, a remote unauthenticated attacker can forge an identity token containing arbitrary identity claims and have it accepted as authentic. In vulnerable deployments, this allows the attacker to create or assume a fully authenticated technician session. The issue affects deployments using configured OIDC providers, including generic OIDC and Azure Active Directory OIDC, under configurations where technician group authenticated logins are enabled.

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation allows a remote unauthenticated attacker to obtain a fully authenticated SimpleHelp technician session and, in practice, administrative or highly privileged control over the SimpleHelp deployment. A compromised technician account can typically remote into managed endpoints, execute scripts, and access remote support functionality across enterprise systems. In some configurations, the flaw also enables bypass of multi-factor authentication because technician accounts can enroll their own MFA method on first login. The resulting impact includes unauthorized access, lateral movement into managed endpoints, malicious script execution, compromise of remote support infrastructure, and potential loss of confidentiality, integrity, and availability.

Mitigation

If you can’t patch tonight, do this now.

If immediate patching is not possible, disable or avoid the vulnerable OIDC authentication method where feasible. Restrict external exposure of SimpleHelp servers, especially public internet access, and limit technician authentication to trusted source IPs using Login Security or equivalent network controls. Review Administration -> Technicians for unexpected group-authenticated users, and inspect server logs in the UI or under /opt/SimpleHelp/logs/ for indicators of compromise. More broadly, reduce exposure of public-facing remote support deployments until patched.

Remediation

Patch, then assume compromise.

Upgrade SimpleHelp to a vendor-fixed release and stop using affected versions 5.5.15 and prior and 6.0 pre-release builds. Apply the vendor security update referenced by SimpleHelp's 2026-05 security update and release materials. After patching, review technician accounts for unauthorized group-authenticated users, inspect server logs for suspicious technician registration and configuration-save events, and remove any attacker-created accounts or persistence established through compromised technician access.
PUBLIC EXPLOITS

Exploits

No public exploits tracked yet. Mallory keeps watching.

VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType
SimpleHelpSimplehelpapplication

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Exposure mapping

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Threat actor evidence

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Associated malware

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Detection signatures

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Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity4

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