CVE-2022-26592 in libsass
Summary
by MITRE • 08/22/2023
Stack Overflow vulnerability in libsass 3.6.5 via the CompoundSelector::has_real_parent_ref function.
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Analysis
by VulDB Data Team • 05/10/2026
The stack overflow vulnerability identified as CVE-2022-26592 represents a critical security flaw within the libsass library version 3.6.5, specifically within the CompoundSelector::has_real_parent_ref function. This vulnerability arises from improper input validation and handling of nested CSS selectors during the compilation process of sass files into css. The libsass library serves as a c++ implementation of sass that is widely used in web development toolchains and build systems, making this vulnerability particularly concerning for developers and organizations relying on sass processing capabilities. The flaw manifests when processing malformed or excessively nested compound selectors that trigger recursive parsing behaviors leading to stack exhaustion.
The technical nature of this vulnerability stems from the CompoundSelector::has_real_parent_ref function failing to properly validate the depth and complexity of selector nesting during the sass compilation phase. When the parser encounters deeply nested or malformed compound selectors, the recursive function calls can exceed the allocated stack space causing a stack overflow condition. This type of vulnerability falls under CWE-121 Stack-based Buffer Overflow, which occurs when a program writes data beyond the bounds of a fixed-length stack buffer. The vulnerability is particularly insidious because it can be triggered through normal sass processing workflows without requiring special privileges or complex attack vectors.
The operational impact of CVE-2022-26592 extends beyond simple denial of service scenarios as it can potentially enable more sophisticated attack vectors within affected systems. Applications that utilize libsass for dynamic sass compilation, such as web frameworks, build tools, and static site generators, become vulnerable to crashes or potential code execution if attackers can control the sass input being processed. This vulnerability directly maps to ATT&CK technique T1203 Exploitation for Client Execution, where adversaries may leverage such memory corruption vulnerabilities to execute arbitrary code. The attack surface is broad as libsass is integrated into numerous development environments and deployment pipelines, including popular frameworks like ruby on rails, node.js applications, and various static site generators that depend on sass processing capabilities.
Mitigation strategies for this vulnerability require immediate action including updating to libsass version 3.6.6 or later where the stack overflow issue has been addressed through proper input validation and stack depth limiting mechanisms. Organizations should implement comprehensive input sanitization practices for any sass content processed through libsass, particularly when dealing with user-provided content or external inputs. The remediation process should also include thorough testing of sass compilation workflows to ensure that recursive selector patterns are properly handled without causing stack exhaustion. Additionally, implementing monitoring and alerting mechanisms around sass compilation processes can help detect unusual processing patterns that might indicate exploitation attempts. Security teams should also consider implementing sandboxing or containerization strategies around sass processing components to limit potential damage should the vulnerability be exploited in environments where immediate patching is not feasible.