SimpleHelp Authentication Bypass via Missing OIDC JWT Signature Verification
Affects SimpleHelp 5.5.0 through 5.5.15 and 6.0 before 6.0 RC2 when OIDC login is enabled for technician groups that allow group authenticated logins. Fixed in 5.5.16 and 6.0 RC2.
- Published
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Listed in CISA KEV
- How many real-world setups can hit the bug, from the vendor's advisory and CISA data. It does not know your setup.What do these mean? →
- Actively exploited
- Fix
- Fixed in 5.5.16, 6.0 RC2
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
- Exploitation: active
- Automatable: yes
- Technical impact: total
Summary
SimpleHelp, a remote support software product, is affected when it is configured to use OpenID Connect (OIDC) login. A remote attacker without credentials could forge a login token to gain full technician access, and in some setups could also bypass multi-factor authentication.
Summarized by anthropic/claude-haiku-5.5. Verify details against the original sources.
Read the original description
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.
Timeline
- CVE published
- Added to CISA KEV
CISA has evidence of exploitation in the wild
- CISA SSVC assessment
Exploitation: active · Automatable: yes · Technical impact: total
- CISA remediation deadline
Due date for US federal agencies to patch
- Record last updated
- EPSS reached 10%
FIRST estimates at least a 10% chance of exploitation in the next 30 days
Affected versions
- SimpleHelp SimpleHelp
From 5.5.0 · fixed in 5.5.16; From 6.0 · fixed in 6.0 RC2
References 3
Questions about CVE-2026-48558
What does this mean?
SimpleHelp does not verify the signature on OIDC JSON Web Tokens, so OIDC-based authentication to the server can be bypassed. The flaw is in how the server accepts those tokens during login.Source: horizon3.ai, simple-help.com
Am I affected, and how do I check?
Versions 5.5.0 up to 5.5.16 and 6.0 up to 6.0 RC2 are in the affected ranges. The setup needs at least one OIDC provider configured, a TechnicianGroup with that provider enabled, and "Allow group authenticated logins" turned on for that group; check these in the server's OIDC and TechnicianGroup settings and check the version in the admin console.Source: horizon3.ai, simple-help.com
What should I do about it?
For 5.5.x, upgrade to SimpleHelp 5.5.16. For the 6.0 line, upgrade to 6.0 RC2 or later.Source: horizon3.ai, simple-help.com
Is it being exploited?
Yes. CISA added it to its Known Exploited Vulnerabilities catalog on 2026-06-29, which means it has evidence of attacks. No public exploit code is tracked.Source: cisa.gov, cve.now feed data