CVE-2026-2869
📋 TL;DR
This CVE describes an out-of-bounds read vulnerability in the janet-lang Janet programming language's handleattr handler. Attackers with local access can exploit this to read sensitive memory contents, potentially exposing credentials or other data. Only systems running Janet versions up to 1.40.1 are affected.
💻 Affected Systems
- janet-lang janet
📦 What is this software?
Janet by Janet Lang
⚠️ Risk & Real-World Impact
Worst Case
Local attacker reads sensitive memory contents including credentials, encryption keys, or other application data, leading to privilege escalation or data breach.
Likely Case
Local user reads limited memory contents, potentially exposing some application data but not full system compromise.
If Mitigated
With proper access controls and isolation, impact is limited to the Janet process's memory space only.
🎯 Exploit Status
Exploit requires local access and knowledge of Janet usage patterns. Public proof-of-concept exists in GitHub repository.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 1.41.0
Vendor Advisory: https://github.com/janet-lang/janet/releases/tag/v1.41.0
Restart Required: Yes
Instructions:
1. Backup current Janet installation
2. Download Janet 1.41.0 from official repository
3. Follow build/installation instructions for your platform
4. Restart any services using Janet
5. Verify version with 'janet -v'
🔧 Temporary Workarounds
Restrict local access
allLimit local user access to systems running vulnerable Janet versions
Disable vulnerable functionality
allAvoid using handleattr functionality in Janet code if possible
🧯 If You Can't Patch
- Isolate Janet applications in containers or VMs with minimal privileges
- Implement strict access controls to limit local user access to affected systems
🔍 How to Verify
Check if Vulnerable:
Run 'janet -v' and check if version is 1.40.1 or earlierCheck Version:
janet -vVerify Fix Applied:
Run 'janet -v' and confirm version is 1.41.0 or later📡 Detection & Monitoring
Log Indicators:
- Unusual Janet process crashes
- Memory access violations in system logs
Network Indicators:
- None - local-only vulnerability
SIEM Query:
Process execution where command contains 'janet' AND version < 1.41.0🔗 References
- https://github.com/janet-lang/janet/
- https://github.com/janet-lang/janet/commit/2fabc80151a2b8834ee59cda8a70453f848b40e5
- https://github.com/janet-lang/janet/issues/1699
- https://github.com/janet-lang/janet/releases/tag/v1.41.0
- https://github.com/oneafter/0123/blob/main/ja1/repro
- https://vuldb.com/?ctiid.347106
- https://vuldb.com/?id.347106
- https://vuldb.com/?submit.754589
