CVE-2026-3390 Overview
A memory safety vulnerability has been identified in FascinatedBox Lily, an open-source programming language implementation. The vulnerability exists within the patch_line_end function located in the src/lily_build_error.c file, which is part of the Error Reporting component. When triggered, the vulnerability causes an out-of-bounds read condition that could allow a local attacker to access memory beyond intended boundaries, potentially leading to information disclosure or denial of service conditions.
Critical Impact
Local attackers with low privileges can trigger an out-of-bounds read in the error reporting component, potentially causing application crashes or memory information disclosure.
Affected Products
- Lily-lang Lily versions up to and including 2.3
- FascinatedBox Lily Error Reporting component (src/lily_build_error.c)
- Systems running affected Lily language interpreter locally
Discovery Timeline
- 2026-03-01 - CVE CVE-2026-3390 published to NVD
- 2026-03-05 - Last updated in NVD database
Technical Details for CVE-2026-3390
Vulnerability Analysis
This vulnerability is classified as an Out-of-Bounds Read (CWE-125), which also falls under the broader category of Improper Restriction of Operations within the Bounds of a Memory Buffer (CWE-119). The flaw resides specifically in the patch_line_end function within the error reporting subsystem of the Lily programming language interpreter.
When the error reporting mechanism attempts to process malformed or specially crafted input, the patch_line_end function fails to properly validate buffer boundaries before performing read operations. This allows the function to read memory beyond the allocated buffer, potentially exposing sensitive memory contents or causing the application to crash.
The vulnerability requires local access to exploit, meaning an attacker would need the ability to execute code or provide input to the Lily interpreter on the target system. While this limits the attack surface compared to remote vulnerabilities, it still presents a significant risk in shared computing environments or scenarios where untrusted Lily scripts are executed.
Root Cause
The root cause of this vulnerability lies in insufficient bounds checking within the patch_line_end function in src/lily_build_error.c. The function processes error message line information during the error reporting phase but does not adequately verify that memory access operations remain within the allocated buffer boundaries. This results in an out-of-bounds read condition when processing certain input patterns.
Attack Vector
The attack vector is local, requiring an attacker to have access to the system where the Lily interpreter is running. Exploitation can be achieved by providing specially crafted input that triggers the error reporting functionality, causing the vulnerable patch_line_end function to read beyond allocated memory boundaries.
A proof-of-concept demonstrating this vulnerability has been documented and reported through the GitHub Issue Tracker. The exploit leverages malformed input that triggers the error reporting code path, causing the out-of-bounds read condition in the boundary patching logic. Technical details and a reproduction case are available in the security researcher's repository.
Detection Methods for CVE-2026-3390
Indicators of Compromise
- Unexpected crashes of the Lily interpreter with memory-related error messages
- Segmentation faults occurring during error handling in Lily applications
- Memory sanitizer reports indicating out-of-bounds read operations in lily_build_error.c
Detection Strategies
- Deploy address sanitizer (ASan) builds of Lily during development and testing to detect out-of-bounds memory accesses
- Monitor system logs for repeated Lily interpreter crashes or segmentation faults
- Implement runtime memory safety tools to catch boundary violations in production environments
Monitoring Recommendations
- Enable core dumps and configure crash analysis tools to identify crashes originating from patch_line_end function
- Monitor for unusual Lily interpreter behavior patterns that may indicate exploitation attempts
- Implement application-level logging to capture error conditions in the error reporting subsystem
How to Mitigate CVE-2026-3390
Immediate Actions Required
- Audit any systems running Lily interpreter versions 2.3 and below for potential exposure
- Restrict execution of untrusted Lily scripts until a patch is available
- Consider implementing sandboxing for Lily interpreter processes to limit impact of potential exploitation
- Monitor the GitHub issue for vendor response and patch availability
Patch Information
As of the last update, the Lily project maintainers have been notified of this vulnerability through a GitHub issue report, but have not yet responded with a patch. Users should monitor the official Lily repository for security updates and apply patches as soon as they become available.
Workarounds
- Restrict access to the Lily interpreter to trusted users only
- Avoid processing untrusted Lily scripts or input until a patch is released
- Deploy the interpreter in a sandboxed environment with limited memory access privileges
- Compile Lily with memory safety tools (ASan, MSan) to detect and halt exploitation attempts during runtime
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
