Vulnerability in Simple-Help Simplehelp
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 10.0 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.777 (99.6th percentile), scored .
High probability of exploitation in the next 30 days — patch promptly. 100th percentile — 99.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.057 · newest: 0.777 · change: +0.719
Affected products
- Simple-Help Simplehelp — versions 6.0
- Simplehelp — versions 5.5.0, 6.0
Weakness classification (CWE)
CISA KEV (Known Exploited Vulnerabilities)
This CVE is on the CISA KEV catalog, added on . CISA KEV inclusion means CISA has confirmed in-the-wild exploitation; US federal agencies are required to remediate within a published due date.
BOD 22-01 due date: .
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.
Public proof-of-concept exploits
References
- horizon3.ai/attack-research/disclosures/cve-2026-48558-simplehelp-authenticatio… (technical-description, Third Party Advisory, exploit)
- simple-help.com/release-news (release-notes, Release Notes)
- simple-help.com/security/simplehelp-security-update-2026-05 (vendor-advisory, Patch, Vendor Advisory)
- 134c704f-9b21-4f2e-91b3-4a467353bcc0 (Technical Description, Third Party Advisory)
- 134c704f-9b21-4f2e-91b3-4a467353bcc0 (US Government Resource)
Frequently asked questions
- What is CVE-2026-48558?
- CVE-2026-48558 is a critical-severity vulnerability in Simple-Help Simplehelp, classified under Improper Verification of Cryptographic Signature. CVSS score: 10.0/10. Published 2026-06-12.
- How severe is CVE-2026-48558?
- Critical severity. CVSS v3 base score is 10.0 out of 10.
- Is CVE-2026-48558 known to be exploited?
- Yes. CVE-2026-48558 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2026-06-29), indicating it is being actively exploited. 2 public proof-of-concept repositories are indexed.