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CVE-2026-48558: SimpleHelp Authentication Bypass Vulnerability

criticalknown exploitedpublic exploitCVE-2026-48558
Actively exploited. At least one CVE in this advisory is listed in the CISA Known Exploited Vulnerabilities catalog — exploitation has been observed in the wild. Treat remediation as 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.

CSIRTS triage

What
An authentication bypass vulnerability allows unauthenticated access to technician sessions.
Who is affected
Users of SimpleHelp with OIDC authentication configured are affected.
Urgency
Remediation is urgent due to active exploitation and critical severity.
Action
Update to the latest version of SimpleHelp.

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Details

Source
CISA Known Exploited Vulnerabilities (US · database · site)
Severity
critical
Published
2026-06-29
Exploitation
Observed in the wild (CISA KEV)

Original advisory: https://nvd.nist.gov/vuln/detail/CVE-2026-48558

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Referenced CVEs

CVECSIRTS overviewExternal
CVE-2026-48558coverage & exploitation statusNVD · CVE.org

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