CVE-2026-48558 SimpleHelp SimpleHelp: security feature bypass
In plain words: A built-in safety check — like a warning before opening a downloaded file — can be skipped. Makes other attacks, like malicious downloads, work without the usual warning.
Confirmed exploited by CISA on · US federal patch deadline Jul 2, 2026
What to do
- Install SimpleHelp's security update for SimpleHelp. If no update exists, follow the vendor's workaround or stop using the product until one ships.
- Keep a list of every internet-facing server you run so nothing is forgotten.
- Patch anything in this catalog first, ahead of normal patch cycles.
- Put admin and file-transfer apps behind a VPN or single sign-on instead of the open internet.
Who is affected
Work IT. Aimed mostly at company systems — you are affected through the companies you use, not your own phone.
What's at risk: Mass data theft and ransomware: a single flaw in a file-transfer or email server has exposed thousands of organisations at once.
The details
- Official name
- SimpleHelp Authentication Bypass Vulnerability
- Product
- SimpleHelp SimpleHelp
- CISA description
- 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.
- Type of flaw
- Security feature bypass (CWE-347)
- Confirmed exploited
- Jun 29, 2026
- US federal patch deadline
- Jul 2, 2026
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Answering about CVE-2026-48558 ·
Questions about CVE-2026-48558
Is CVE-2026-48558 being exploited?
Yes. CISA added CVE-2026-48558 to its Known Exploited Vulnerabilities catalog on Jun 29, 2026, which means there is reliable evidence of real-world attacks.
How do I fix CVE-2026-48558?
Install SimpleHelp's security update for SimpleHelp. If no update exists, follow the vendor's workaround or stop using the product until one ships. Keep a list of every internet-facing server you run so nothing is forgotten.
Am I affected by CVE-2026-48558?
Only if you use SimpleHelp SimpleHelp. Aimed mostly at company systems — you are affected through the companies you use, not your own phone.