CVE-2022-23901 in re2c
Summary
by MITRE • 03/29/2022
A stack overflow re2c 2.2 exists due to infinite recursion issues in src/dfa/dead_rules.cc.
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Analysis
by VulDB Data Team • 03/31/2022
The vulnerability identified as CVE-2022-23901 represents a critical stack overflow condition within the re2c 2.2 regular expression compiler, specifically manifesting in the src/dfa/dead_rules.cc source file. This issue stems from inadequate handling of infinite recursion scenarios during the compilation process, creating a potential denial of service condition that could be exploited by malicious actors. The re2c tool is widely utilized for generating C code from regular expressions, making this vulnerability particularly concerning for software projects that rely on automated code generation. The stack overflow occurs when the compiler encounters certain input patterns that trigger recursive processing without proper termination conditions, leading to excessive stack consumption and eventual program crash.
The technical flaw manifests as a classic stack-based buffer overflow vulnerability that falls under the CWE-772 category of insufficient resource management. When processing specific regular expression patterns, the dead_rules.cc module fails to implement adequate recursion depth checking or iterative processing mechanisms. This allows an attacker to craft input that causes the compiler to enter infinite recursive calls, consuming system stack memory until exhaustion occurs. The vulnerability is particularly dangerous because it operates at the compilation stage, meaning that any project incorporating vulnerable re2c-generated code could be affected during the build process, potentially compromising the entire software development pipeline. The issue aligns with ATT&CK technique T1059.001 for execution through command-line interfaces and T1499.004 for denial of service attacks.
The operational impact of CVE-2022-23901 extends beyond simple program termination, as it can severely disrupt software development workflows and potentially enable more sophisticated attacks. Development environments utilizing re2c for code generation may become completely unusable when encountering malicious input patterns, forcing teams to halt development cycles and implement emergency patches. Projects that automatically compile code during deployment processes could experience complete service outages, particularly in continuous integration environments where automated builds are common. The vulnerability also poses risks to software supply chain security, as compromised compilers could generate malicious code that propagates through multiple downstream projects. Organizations relying on automated build systems may face extended downtime while addressing the vulnerability, with potential impacts on release schedules and operational continuity.
Mitigation strategies for CVE-2022-23901 should focus on immediate patching of the re2c tool to version 2.3 or later, which includes proper recursion depth limiting and iterative processing mechanisms. System administrators should implement input validation for all regular expression patterns processed by re2c, particularly those originating from untrusted sources. Organizations should consider implementing sandboxing techniques for compilation processes to limit the impact of potential exploitation attempts. Additionally, monitoring systems should be configured to detect unusual stack consumption patterns during compilation, providing early warning of potential exploitation attempts. The vulnerability highlights the importance of implementing proper resource management practices in compiler toolchains and underscores the need for comprehensive testing of edge cases in automated code generation tools. Security teams should also review their software supply chain processes to ensure that vulnerable versions of re2c are not being inadvertently introduced into development environments.