CVE-2026-1842
📋 TL;DR
HyperCloud versions 2.3.5 through 2.6.8 have an authentication flaw where refresh tokens can be used directly for resource access instead of just obtaining new access tokens. Additionally, old access tokens remain valid after refresh. This allows attackers with stolen tokens to maintain prolonged unauthorized access to systems.
💻 Affected Systems
- HyperCloud
⚠️ Manual Verification Required
This CVE does not have specific version information in our database, so automatic vulnerability detection cannot determine if your system is affected.
Why? The CVE database entry doesn't specify which versions are vulnerable (no version ranges provided by the vendor/NVD).
🔒 Custom verification scripts are available for registered users. Sign up free to download automated test scripts.
- Review the CVE details at NVD
- Check vendor security advisories for your specific version
- Test if the vulnerability is exploitable in your environment
- Consider updating to the latest version as a precaution
⚠️ Risk & Real-World Impact
Worst Case
An attacker with a stolen refresh token gains persistent unauthorized access to all resources the token authorizes for up to one year, potentially leading to data theft, privilege escalation, or system compromise.
Likely Case
Attackers use leaked refresh tokens to maintain access to cloud resources, enabling data exfiltration, unauthorized API calls, or lateral movement within the environment.
If Mitigated
With proper token monitoring and short session timeouts, impact is limited to temporary unauthorized access until tokens expire or are revoked.
🎯 Exploit Status
Exploitation requires obtaining a valid refresh token through other means (phishing, credential theft, etc.), but once obtained, using it is trivial.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 2.6.9 or later
Vendor Advisory: https://advisories.softiron.cloud/
Restart Required: Yes
Instructions:
1. Backup current configuration. 2. Upgrade HyperCloud to version 2.6.9 or later. 3. Restart all HyperCloud services. 4. Force token rotation for all users.
🔧 Temporary Workarounds
Reduce Refresh Token Lifetime
allConfigure refresh tokens to have shorter expiration times to limit exposure window
hypercloud config set auth.refresh_token_lifetime=24h
Implement Token Revocation
allManually revoke all existing refresh tokens and force re-authentication
hypercloud auth revoke-all-tokens
🧯 If You Can't Patch
- Implement network segmentation to limit access from systems using vulnerable tokens
- Deploy additional authentication layers (MFA, IP whitelisting) for sensitive resources
🔍 How to Verify
Check if Vulnerable:
Check HyperCloud version with 'hypercloud version' and verify it's between 2.3.5 and 2.6.8 inclusiveCheck Version:
hypercloud versionVerify Fix Applied:
After patching, test that refresh tokens cannot be used for direct resource access and that old access tokens are invalidated upon refresh📡 Detection & Monitoring
Log Indicators:
- Multiple access attempts using same refresh token
- Access tokens used beyond their intended expiration
- Unusual token usage patterns from same client
Network Indicators:
- API calls using refresh tokens in Authorization header
- Sustained access from single token over extended period
SIEM Query:
auth_token_type="refresh" AND http_method!="POST" AND http_path!="/oauth/token"