CVE-2026-48558
SimpleHelp — SimpleHelp Authentication Bypass Vulnerability
SimpleHelp · CWE-347 · in CISA KEV since 2026-06-29
EVRS 75 of 100 Urgent
Patch This Cycle
Rank 1,098 of 2,960 tracked
Raised to the floor for a confirmed exploited vulnerability.
Why it scores 75
Evidence available: 6 of 7 signalsListed in the CISA KEV catalog, and an EPSS probability of 0.057.
- CISA KEVApplied
- RansomwareDid not apply
- Vendor exploitationDid not apply
- EPSSApplied
- Microsoft Exploitability IndexNot applicable
- Pre-patch disclosureNo data
- KEV recencyDid not apply
- CVSSApplied
The band answers “how soon”, not “how bad”. No data for: Pre-patch disclosure. Why some signals show no data
Fix
Patch or fixed version identifiedCISA required action
- simple-help.com/…/simplehelp-security-update-2026-05
- BOD 26-04
- Forensics Triage Requirements
- nvd.nist.gov/…/CVE-2026-48558
Fixed in
simplehelp: update to 5.5.16 or later
Affected versions
- simplehelp
< 5.5.166.0
Remediation
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.
Fixed versions from NVD.
Evidence
Each value with its source| Measure | Value | Source |
|---|---|---|
| CVSS base scoreHow severe the flaw is in itself. It does not say how likely an attack is. | 9.5 | NVD |
| FIRST EPSSFIRST's estimate of the chance this is exploited in the next 30 days, and how that ranks against all CVEs. | 0.057 (93rd pctl) | FIRST EPSS |
| Actively exploitedWhether a source of record has confirmed attacks using it in the wild. | Confirmed | CISA KEV |
| Ransomware campaign useWhether CISA has seen ransomware operators use it. | Unknown or none | CISA KEV |
| CISA remediation deadlineThe date US federal agencies must have fixed or mitigated it. | 2026-07-02 · CISA federal deadline · Overdue by 4 months | CISA KEV |
| Public exploit moduleA module existing is not the same as active exploitation. | Public module exists | Metasploit |
| EUVD cross-referenceENISA's record: CVSS 9.5 (v4.0), assigned by VulnCheck. | Listed | ENISA EUVD |
Description
NVDSimpleHelp 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.
What CISA says to do
- simple-help.com/…/simplehelp-security-update-2026-05
- BOD 26-04
- Forensics Triage Requirements
- nvd.nist.gov/…/CVE-2026-48558
Public module
Metasploit lists a public excellent-rank module for this CVE: SimpleHelp OIDC Authentication Bypass Remote Code Execution (multi/http/simplehelp_oidc_auth_bypass_rce). A module existing is not the same as active exploitation; see metasploit.com.
