The CVE-2021-42836 vulnerability affects versions of the gjson library prior to 1.9.3. This vulnerability allows a ReDoS (regular expression denial of service) attack, which can significantly impact the availability of applications utilizing this library. The CVSS score for this vulnerability is 7.5, categorizing it as a high-severity issue. The potential for service disruption underscores the importance of addressing this vulnerability promptly.
Risk to organizations includes application downtime and degraded performance due to the ReDoS attack vector, which exploits the library's regular expression handling. Attackers may leverage this vulnerability to create crafted JSON input that leads to denial of service, thereby affecting the integrity of service availability.
Organizations should prioritize patching immediately to mitigate this risk. The last modification to this CVE was noted on November 21, 2024, indicating ongoing relevance and potential for exploitation if not addressed. It is essential for security teams to stay updated on such vulnerabilities, especially those with high availability impact.
This vulnerability has not been included in the KEV (Known Exploited Vulnerabilities) catalog, but the lack of public exploits does not diminish its risk. Organizations must take proactive measures to ensure their systems are secured against this threat.
Vulnerability Details
The CVE-2021-42836 vulnerability allows a ReDoS (regular expression denial of service) attack. According to the NVD, the vulnerability was published on October 22, 2021, and affects gjson versions prior to 1.9.3. The vulnerability's CVSS score is 7.5, indicating a high severity level due to its potential availability impact. The CWE classification associated with this vulnerability is CWE-400.
Technical Analysis
The root cause of CVE-2021-42836 lies in the way gjson handles regular expressions. The attack vector is network-based, allowing attackers to exploit the vulnerability remotely without requiring authentication or user interaction. The complexity of the attack is low, making it easier for attackers to trigger the denial of service condition.
Specifically, the ReDoS attack can occur when an attacker sends specially crafted JSON input that causes the application to hang while processing the regular expression. This results in high availability impact as the application becomes unresponsive during the processing of malicious input.
Risk & Impact Analysis
The real-world deployment risk associated with CVE-2021-42836 is significant. Organizations utilizing gjson in production environments should be aware of the potential service disruption caused by this vulnerability. The blast radius is broad, affecting any application that relies on gjson for JSON parsing. Urgency for remediation is high due to the CVSS score of 7.5 and the potential for exploitation.
Organizations should address this vulnerability in their priority patch cycle to prevent attackers from leveraging it to cause denial of service. The lack of public exploits does not negate the need for immediate action, as attackers can easily adapt and develop new exploitation techniques.
Exploitation Status
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
GJSON versions prior to 1.9.3 are affected by this vulnerability. Organizations should ensure they are running the latest version to mitigate this risk.
Mitigation & Remediation
To mitigate CVE-2021-42836, organizations should upgrade to GJSON version 1.9.3 or later. If an immediate upgrade is not possible, consider implementing application-level safeguards to limit input size and complexity. Additionally, monitoring for unusual patterns or input that could trigger the vulnerability is advisable. Organizations can explore penetration testing services to validate the effectiveness of any implemented mitigations.
Detection Guidance
Monitor logs for indicators of repeated calls to gjson processing with complex regular expressions. Behavioral anomalies may include increased latency in response times when processing specific JSON inputs. Additionally, implement network signatures to detect unusual patterns that could signify an attempted ReDoS attack.
AppSecure Threat Intelligence Insight
The long-term significance of CVE-2021-42836 lies in its representation of the risks associated with regular expression handling in JSON libraries. It highlights the need for robust input validation and processing restrictions to prevent denial of service vulnerabilities. Security teams should take lessons from this vulnerability to evaluate their own input processing and validation mechanisms, ensuring that they are resilient against similar threats. Organizations can refer to the following resources for further guidance on enhancing application security:
Application security assessment can provide insights into potential vulnerabilities.
Penetration testing methodology offers a structured approach to identifying security weaknesses.
Vulnerability management programs should be designed to proactively address and remediate issues as they arise.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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