CVE-2026-1229
📋 TL;DR
A cryptographic vulnerability in CIRCL's P-384 elliptic curve implementation produces incorrect CombinedMult results for specific inputs. This affects applications using the vulnerable function for cryptographic operations, potentially leading to incorrect cryptographic outputs. Only systems using the affected CIRCL package with the CombinedMult function on the secp384r1 curve are impacted.
💻 Affected Systems
- cloudflare/circl
📦 What is this software?
Circl by Cloudflare
⚠️ Risk & Real-World Impact
Worst Case
Cryptographic operations produce incorrect results, potentially enabling cryptographic attacks against systems relying on the CombinedMult function for security-critical operations.
Likely Case
Applications using CombinedMult may produce incorrect cryptographic outputs, potentially causing functional failures or security weaknesses in specific scenarios.
If Mitigated
ECDH and ECDSA operations are unaffected, limiting impact to specific CombinedMult usage patterns.
🎯 Exploit Status
Exploitation requires specific inputs to trigger the bug and understanding of CombinedMult usage patterns.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: v1.6.3
Vendor Advisory: https://github.com/cloudflare/circl/releases/tag/v1.6.3
Restart Required: Yes
Instructions:
1. Check current CIRCL version
2. Update to v1.6.3 or later using package manager
3. Restart affected applications
🔧 Temporary Workarounds
Avoid CombinedMult usage
allTemporarily avoid using CombinedMult function on secp384r1 curve
🧯 If You Can't Patch
- Disable or avoid using CombinedMult function in affected applications
- Implement additional validation of cryptographic outputs
🔍 How to Verify
Check if Vulnerable:
Check if application imports github.com/cloudflare/circl/ecc/p384 and uses CombinedMult functionCheck Version:
go list -m github.com/cloudflare/circlVerify Fix Applied:
Verify CIRCL version is v1.6.3 or later and test CombinedMult with known test vectors📡 Detection & Monitoring
Log Indicators:
- Unexpected cryptographic operation failures
- Application errors related to CombinedMult function
Network Indicators:
- None specific to this vulnerability
SIEM Query:
Application logs containing 'CombinedMult' errors or cryptographic operation failures