CVE-2025-9403 in jqlang
Summary
by MITRE • 08/25/2025
A vulnerability was determined in jqlang jq up to 1.6. Impacted is the function run_jq_tests of the file jq_test.c of the component JSON Parser. Executing manipulation can lead to reachable assertion. The attack requires local access. The exploit has been publicly disclosed and may be utilized. Other versions might be affected as well.
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Analysis
by VulDB Data Team • 05/31/2026
The vulnerability identified as CVE-2025-9403 affects the jqlang jq library version 1.6 and earlier, specifically within the run_jq_tests function located in jq_test.c. This represents a critical security flaw in the JSON parser component that could potentially allow attackers with local system access to trigger assertion failures. The vulnerability stems from insufficient input validation and error handling mechanisms within the testing framework, creating a condition where malformed or manipulated inputs can cause the application to terminate unexpectedly or behave unpredictably. The assertion failure occurs during the execution of JSON parsing operations, indicating a fundamental breakdown in the library's ability to handle edge cases or malicious inputs gracefully. Given that the exploit requires only local access, this vulnerability presents a significant risk in environments where local privilege escalation or code execution opportunities exist, as it could serve as a stepping stone for more severe attacks.
The technical implementation of this vulnerability demonstrates a classic buffer over-read or invalid memory access scenario, where the run_jq_tests function fails to properly validate input parameters before processing them through the JSON parsing engine. The flaw likely involves improper bounds checking or incorrect handling of parsed JSON structures that could lead to memory corruption or assertion violations. According to CWE classification systems, this vulnerability aligns with CWE-682, which covers computations that are incorrect, and potentially CWE-129, which addresses insufficient validation of array indices. The vulnerability's impact is amplified by the fact that it exists within a testing function that may be executed during library initialization or integration processes, meaning that even legitimate usage could trigger the assertion failure. The public disclosure of this exploit increases the likelihood of real-world exploitation, particularly in environments where jqlang jq is used for processing untrusted JSON data, making it a high-priority concern for system administrators and security teams.
The operational impact of CVE-2025-9403 extends beyond simple assertion failures to potentially enable more sophisticated attack vectors. While the immediate effect may appear as application crashes or assertion violations, attackers could leverage this vulnerability to create denial of service conditions that disrupt legitimate operations. In environments where jqlang jq is integrated into larger applications or services, this vulnerability could be exploited to cause cascading failures or to gain insights into system behavior through controlled crashes. The vulnerability's presence in the testing framework also raises concerns about potential information disclosure, as assertion failures might reveal internal system states or memory layouts that could aid in further exploitation attempts. From an ATT&CK framework perspective, this vulnerability could be categorized under T1499.004 for network denial of service and potentially T1059.007 for command and scripting interpreter usage, depending on how it's leveraged within a broader attack chain. Organizations using this library should consider the potential for privilege escalation if local access is obtained through other means, as the assertion failure could be exploited to manipulate program flow or inject malicious code into memory segments.
Mitigation strategies for CVE-2025-9403 should prioritize immediate remediation through version updates to jqlang jq 1.7 or later, where the vulnerability has been addressed through proper input validation and error handling improvements. System administrators should conduct comprehensive inventory assessments to identify all systems utilizing affected versions of the library, particularly in environments where local access is possible or where the library is used in security-critical applications. Additionally, implementing runtime protections such as address space layout randomization and stack canaries can help mitigate potential exploitation attempts, though these measures do not address the root cause. Organizations should also consider deploying intrusion detection systems that can monitor for abnormal assertion failures or application crashes that might indicate exploitation attempts. The vulnerability's location within the testing framework suggests that disabling or restricting access to test functions in production environments could serve as a temporary workaround, though this approach is less ideal than proper patching. Regular security assessments should include verification of library versions and their compliance with security best practices, particularly for open source components that may not receive regular security updates from vendors. Security teams should also monitor for additional vulnerabilities in similar JSON parsing libraries and ensure that their incident response procedures account for potential assertion failure exploitation scenarios.