# CVE-2026-48558 — SimpleHelp

> As of 2026-06-13, CVE-2026-48558 is a CRITICAL-severity vulnerability in SimpleHelp, CVSS v3.1 10, EPSS 0.7% (49.2th percentile). Threadlinqs Intelligence links 2 tracked threat campaigns to CVE-2026-48558, most recently “SimpleHelp Authentication Bypass via Forged OIDC Tokens (CVE-2026-48558) Actively Exploited, Added to CISA KEV”.

**Last updated:** 2026-06-13

## What is CVE-2026-48558?

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.

The record classifies CVE-2026-48558 under weakness class [CWE-347](https://cwe.mitre.org/data/definitions/347.html). Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs no prior authentication, needs no user interaction, and has high impact on confidentiality, integrity, availability. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 93 days ago.

## Severity and exploitation probability

- **CVSS v3.1 base score:** 10 — CRITICAL (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H`)
- **CVSS v4.0 base score:** 9.5 (`CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H`)
- **EPSS (FIRST):** 0.7% probability of exploitation in the next 30 days, higher than 49.2% of all scored CVEs
- **CISA KEV:** Not listed in the CISA Known Exploited Vulnerabilities catalog
- **Threadlinqs priority:** 7/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- **Published:** 2026-06-12, last modified 2026-06-13

## Is CVE-2026-48558 being exploited?

No public exploitation evidence for CVE-2026-48558 is recorded in the sources Threadlinqs tracks — CISA KEV, Exploit-DB, public proof-of-concept repositories and ProjectDiscovery Nuclei — as of 2026-06-13. That is an absence of evidence in those feeds, not a guarantee that the vulnerability is unexploited.

## Affected products and versions

- **SimpleHelp**: SimpleHelp

## How to fix CVE-2026-48558

No vendor patch reference has been recorded for CVE-2026-48558 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.

## Threat activity tracking CVE-2026-48558

2 tracked threats in the Threadlinqs corpus reference CVE-2026-48558, either in the campaign’s CVE list or as an indicator on the campaign record.

- [SimpleHelp Authentication Bypass via Forged OIDC Tokens (CVE-2026-48558) Actively Exploited, Added to CISA KEV](https://intel.threadlinqs.com/threat/TL-2026-1122) — CRITICAL · 2026-07-05
- [SimpleHelp RMM OIDC Authentication Bypass (CVE-2026-48558) — Unauthenticated Forged-Token Technician Account Creation and MFA Bypass](https://intel.threadlinqs.com/threat/TL-2026-0820) — CRITICAL · 2026-06-16

## Sources

Enriched from CVE.org, NVD, FIRST EPSS, GitHub Security Advisories. Last verified by Threadlinqs on 2026-06-26. This product uses the NVD API but is not endorsed or certified by the NVD.

**Vendor advisory and patch**

- [simple-help.com — vendor advisory](https://simple-help.com/security/simplehelp-security-update-2026-05)
- [simple-help.com — release notes](https://simple-help.com/release-news)

**Exploit and proof of concept**

- [horizon3.ai — technical description](https://horizon3.ai/attack-research/disclosures/cve-2026-48558-simplehelp-authentication-bypass-iocs/)

Canonical: https://intel.threadlinqs.com/cve/CVE-2026-48558
Full detection coverage and IOCs for threats exploiting CVE-2026-48558 via the Threadlinqs MCP server (Purple tier): https://intel.threadlinqs.com/mcp