CVE-2026-48558
SimpleHelp versions 5.5.15 and prior and 6.0 pre-release versions contain an authentication bypass vulnerability in the OIDC authentication flow.
- Severity
- 9.5 / 10
- Critical · CVSS 4.0
- Exploit chance (EPSS)
- 77.66%
- Chance of exploitation in the next 30 days. Higher than 99.56% of scored vulnerabilities.
- Known exploited
- Yes
- In CISA's catalog since Jun 29, 2026
- Weakness
- CWE-347 Improper Verification of Cryptographic Signature
- Fix
- None yet
- No fixed version published
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.
How to fix
No fixed version has been published yet. Until one is, remove or replace the package, or turn off or isolate the affected feature. This page updates when a fix ships.
Severity breakdown
CVSS 4.0 9.5
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
- Attack vector
- Network
- Attack complexity
- Low
- Attack requirements
- Present
- Privileges required
- None
- User interaction
- None
- Confidentiality (vulnerable system)
- High
- Integrity (vulnerable system)
- High
- Availability (vulnerable system)
- High
- Confidentiality (subsequent systems)
- High
- Integrity (subsequent systems)
- High
- Availability (subsequent systems)
- High
- Exploit maturity
- Not defined
- Scope
- X
CVSS 3.1 10.0
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Changed
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Weakness
CWE-347: Improper Verification of Cryptographic Signature
The product does not verify, or incorrectly verifies, the cryptographic signature for data.
References
Advisories
Other links
Timeline
- Published
- Added to CISA's Known Exploited Vulnerabilities catalog
- Remediation due for U.S. federal agencies
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| EEF-CVE-2026-65632 ECDSA signature length is not validated in jose, allowing signature malleability | Not rated yet | Same weakness, CWE-347 |
| GHSA-pxh4-856f-4h89 PyJWT: HS256/384/512 verify accepts empty HMAC key via oct JWK (PyJWK/PyJWKClient) enabling token forgery | High | Same weakness, CWE-347 |
| GHSA-j7h2-66j4-ghjf A russh SSH server accepts a publickey authentication whose signature uses a different algorithm than the one named in the request | Low | Same weakness, CWE-347 |
| GHSA-w2cx-738m-mc7w PyJWT accepts public JWK containers as HMAC secrets | High | Same weakness, CWE-347 |
| GHSA-r6x4-923q-g947 PyJWT BOM Bypass | High | Same weakness, CWE-347 |
| GHSA-p4g4-x82p-q773 PyJWT: Public keys in DER form are accepted as HMAC secrets, bypassing the CVE-2022-29217 guard | High | Same weakness, CWE-347 |
| GHSA-ffc3-869f-jxw9 PyJWT: Asymmetric-PEM detection bypass: whitespace/line-ending-mutated public keys skip the HS/asymmetric confusion guard | Critical | Same weakness, CWE-347 |
| GHSA-9j54-fg26-wv3r PyJWT: PyJWK accepts empty HMAC keys, bypassing PyJWT's empty-key validation | Critical | Same weakness, CWE-347 |
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