CVE-2021-28307 in fltk Crate
Summary
by MITRE • 03/12/2021
An issue was discovered in the fltk crate before 0.15.3 for Rust. There is a NULL pointer dereference during attempted use of a non-raster image for a window icon.
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Analysis
by VulDB Data Team • 04/01/2021
The vulnerability identified as CVE-2021-28307 affects the fltk crate version 0.15.2 and earlier in the Rust programming language ecosystem. This issue manifests as a NULL pointer dereference when the system attempts to process a non-raster image for window icon display. The fltk crate serves as a Rust binding for the FLTK (Fast Light Toolkit) graphical user interface library, which is widely used for creating cross-platform desktop applications. When developers utilize this crate to set window icons, particularly with non-raster image formats, the application encounters a critical failure during runtime execution.
The technical flaw stems from inadequate input validation within the image processing pipeline of the fltk crate. Specifically, when a non-raster image type is provided as a window icon parameter, the code path fails to properly handle the NULL pointer scenario that occurs during the image conversion or rendering process. This NULL pointer dereference represents a classic software vulnerability pattern that can lead to application crashes, potentially enabling denial of service attacks against systems using affected versions. The vulnerability falls under the CWE-476 category of NULL Pointer Dereference, which is classified as a common weakness in software development practices.
The operational impact of this vulnerability extends beyond simple application instability. In environments where the affected software is deployed as a critical service or desktop application, a malicious actor could potentially trigger this condition through crafted input, leading to system unavailability or service disruption. The vulnerability is particularly concerning in applications that dynamically load window icons from external sources or user-provided content, as these scenarios increase the likelihood of encountering non-raster image formats. From an attacker perspective, this vulnerability aligns with ATT&CK technique T1499.004 for Network Denial of Service and T1553.001 for Subvert Trust Controls, as it can be exploited to compromise system availability.
Mitigation strategies for CVE-2021-28307 primarily involve upgrading to fltk crate version 0.15.3 or later, which contains the necessary patches to properly handle NULL pointer scenarios during image processing. System administrators and developers should conduct thorough testing of their applications after applying the upgrade to ensure compatibility with the fixed implementation. Additionally, implementing proper input validation at the application level can provide defense-in-depth measures, ensuring that only supported image formats are processed for window icons. Organizations should also consider monitoring their software supply chains for similar vulnerabilities in other GUI libraries and dependencies that might exhibit analogous NULL pointer dereference behaviors. The fix implemented in version 0.15.3 demonstrates proper error handling mechanisms that prevent the application from crashing when encountering unexpected image formats, thereby improving the overall robustness and security posture of Rust applications utilizing this crate.