CVE-2026-48558
SimpleHelp Authentication Bypass via Missing OIDC JWT Signature Verification
- Published
- Updated
- Reserved
- Assigned by
- VulnCheck
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.
Exploited in the wild
CISA lists this vulnerability in its Known Exploited Vulnerabilities catalog as SimpleHelp Authentication Bypass Vulnerability.
- Added
- 29 Jun 2026
- Fix due (US federal)
- 2 Jul 2026
- Used by ransomware
- Not known
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 exploit
A reference of the record is tagged as an exploit or proof of concept: anyone can try it against an unpatched system. CISA's SSVC rates its exploitation: it is being exploited.
Timeline
ID reserved
By VulnCheck
- 22 days later
· 22 days later
Published
- 17 days later
· 17 days later
Added to CISA KEV
Known exploited in the wild
- 3 months later
· 3 months later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| VulnCheckCNA (assigner) | 4.0 | Critical9.5 | CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H |
| VulnCheckCNA (assigner) | 3.1 | Critical10.0 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H |
| NVDNVD · Analyzed | 4.0 | Critical9.5 | CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X |
- EPSS (exploitation in 30 days)
- 80.8% · top 0.4% of all CVEs (7 Nov 2026)
- CISA SSVC
- Exploitation: active · Automatable: yes · Technical impact: total
The list uses the assigner's score when there is one, then CISA's, then NVD's: Critical 9.5.
Weakness
Affected products
- affected 5.5.0 – < 5.5.16
- affected 6.0 – < 6.0 RC2
References (5)
- https://horizon3.ai/attack-research/disclosures/cve-2026-48558-simplehelp-authentication-bypass-iocs/ (opens in a new tab)technical-descriptionexploit
- https://simple-help.com/security/simplehelp-security-update-2026-05 (opens in a new tab)vendor-advisory
- https://simple-help.com/release-news (opens in a new tab)release-notes
- https://blackpointcyber.com/blog/a-djinn-in-the-machine-taskweavers-node-js-intrusion-chain/ (opens in a new tab)third-party-advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-48558 (opens in a new tab)government-resource
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- CISA KEV catalog (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2026-48558)Record last updated .