---
title: "CVE-2026-48558: SimpleHelp Authentication Bypass Vulnerability"
url: https://erroneo.us/security/cve/CVE-2026-48558/
description: "CVE-2026-48558 (SimpleHelp SimpleHelp): Exploited in the wild (CISA KEV). SimpleHelp versions 5.5.15 and prior and 6.0 pre-release versions contain an…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-06-12
date_modified: 2026-10-07
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-48558"
kev: true
cvss: 9.5
epss: 0.05719
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2026-48558: SimpleHelp Authentication Bypass Vulnerability

**Signal:** Exploited: patch now if you run it. CISA has confirmed exploitation in the wild. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- Yes, if you run SimpleHelp SimpleHelp. CISA added this CVE to its Known Exploited Vulnerabilities catalog on 2026-06-29, which means there is reliable evidence of exploitation in the wild. US federal agencies must remediate by 2026-07-02 ; treat that as the outer limit, not the target.
- EPSS 5.7% , percentile 93: FIRST’s model estimates a 5.7% chance of exploitation activity in the next 30 days, higher than 93% of all scored CVEs (elevated). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.

## What it is

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 products (CVE record)

- SimpleHelp SimpleHelp: 5.5.0 < 5.5.16, 6.0 < 6.0 RC2

## Severity

- VulnCheck CVSS 4.0: 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`
- VulnCheck CVSS 3.1: 10 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H`

## Exploitation

- CISA KEV: added 2026-06-29; federal due date 2026-07-02. Known ransomware use: Unknown.
- CISA 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.
- CISA SSVC assessment: exploitation active , automatable yes , technical impact total .
- FIRST EPSS (model of 2026-10-21): 5.72% probability of exploitation activity in the next 30 days; percentile 93.

## Sources

- [simple-help.com](https://simple-help.com/security/simplehelp-security-update-2026-05)
- [simple-help.com](https://simple-help.com/release-news)
- [CVE.org record CVE-2026-48558](https://www.cve.org/CVERecord?id=CVE-2026-48558)
- [NVD entry CVE-2026-48558](https://nvd.nist.gov/vuln/detail/CVE-2026-48558)
- [CISA Known Exploited Vulnerabilities catalog entry](https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-48558)
- [Listed in CISA KEV notes (cisa.gov)](https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk)
- [Listed in CISA KEV notes (cisa.gov)](https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk)
- [horizon3.ai](https://horizon3.ai/attack-research/disclosures/cve-2026-48558-simplehelp-authentication-bypass-iocs/)
- [blackpointcyber.com](https://blackpointcyber.com/blog/a-djinn-in-the-machine-taskweavers-node-js-intrusion-chain/)

---
Source page: https://erroneo.us/security/cve/CVE-2026-48558/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt