CVE-2026-48558

SimpleHelp Authentication Bypass via Missing OIDC JWT Signature Verification

CRITICAL
10
CVSS Score
Published: June 12, 2026 at 05:07 PM UTC
Updated: October 7, 2026 at 08:17 PM UTC
2 products affected across 1 vendorSimplehelpSimplehelp

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Severity
CRITICAL10
Exploitation
CISA KEV
Exploit prediction
EPSS 78%
SSVC
Active

Actively Exploited

CISA Known Exploited Vulnerabilities (KEV) Catalog

EPSS Score77.7%

EPSS (Exploit Prediction Scoring System) estimates a 77.7% chance this CVE is exploited in the wild within the next 30 days — higher than 100% of all CVEs. It complements CVSS: a high EPSS on a mid-severity CVE can still be urgent.

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.

Required Action
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.
Ransomware Use
Unknown
Added to KEV
Jun 29, 2026
Remediation Due
Jul 2, 2026
121 days overdue

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 5.5.165.5.0 ≤ v < 5.5.166.0 ≤ v < 6.0 rc26.0 pre-release
Affected range stops below 5.5.16, so it looks safe — our inference, not a vendor statement
Affected range stops below 6.0 rc2, so it looks safe — our inference, not a vendor statement
5.5.0 ≤ v < 5.5.166.0 ≤ v < 6.0 RC25.5.06.0
Affected range stops below 5.5.16, so it looks safe — our inference, not a vendor statement
Affected range stops below 6.0 RC2, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (5)

Release Notes
Source: cverecord
https://simple-help.com/release-news
Technical DescriptionThird Party Advisory
Source: 134c704f-9b21-4f2e-91b3-4a467353bcc0
https://blackpointcyber.com/blog/a-djinn-in-the-machine-taskweavers-node-js-intrusion-chain/
US Government Resource
Source: 134c704f-9b21-4f2e-91b3-4a467353bcc0
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-48558

SSVC — Action Prioritization

SSVCActiveAutomatableTotal impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

10CRITICALVulnCheck
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
CHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
CWE-347

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