CVE-2021-26271 identifies a medium-severity vulnerability present in CKEditor 4 prior to version 4.16. This vulnerability allows attackers to execute a ReDoS-type attack by persuading victims to paste specially crafted text into the Styles input of specific dialogs, particularly in the Advanced Tab for the Dialogs plugin. The potential impact of this vulnerability is notable due to its ability to disrupt service availability.
The CVSS score for this vulnerability is 6.5, indicating a medium severity level. The attack vector is classified as network-based with a low attack complexity, requiring no privileges but necessitating user interaction. The availability impact is high, which underscores the importance of addressing this vulnerability proactively.
Risk to organizations includes the potential for significant disruption, especially for those utilizing CKEditor in web applications. The urgency for defenders is clear; organizations should prioritize patching immediately to mitigate risks associated with this vulnerability.
Currently, there are no known exploits, and it is not included in the Known Exploited Vulnerabilities (KEV) catalog. However, the absence of known exploits does not diminish the need for remediation, as the attack vector remains viable.
Vulnerability Details
This vulnerability allows for the execution of a ReDoS-type attack inside CKEditor 4 before version 4.16. The attack can be initiated by persuading a victim to paste crafted text into specific dialog inputs. The official description states that this issue affects the Advanced Tab for the Dialogs plugin.
The CVSS score of 6.5 indicates a medium severity level, with a high availability impact. The vulnerability is classified under the Common Weakness Enumeration (CWE) as CWE-829, which pertains to regular expression denial of service.
Technical Analysis
The root cause of this vulnerability is related to how CKEditor processes input in certain dialog fields. By submitting crafted input, an attacker can exploit the regular expression processing, leading to a denial of service condition.
The attack vector is network-based, requiring low complexity for execution. No privileges are needed to initiate the attack, but user interaction is required since the victim must paste the crafted text into the application. The impacts on confidentiality and integrity are negligible, while the availability impact is high, making this a serious concern for affected organizations.
Risk & Impact Analysis
Real-world deployment risk associated with CVE-2021-26271 is significant, particularly for organizations relying on CKEditor for web content management. The potential blast radius is concerning, with the possibility of widespread service disruption affecting all users interacting with the compromised CKEditor instance.
Organizations using unsupported versions are particularly vulnerable. Although the CVSS score indicates a medium level of severity, the availability impact emphasizes the urgency for remediation. Organizations should address this vulnerability in priority patch cycles to prevent service outages.
Exploitation Status
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
CKEditor versions prior to 4.16 are affected by this vulnerability. Additionally, several Oracle products, including Agile PLM (versions 9.3.5 and 9.3.6), Application Express, and web-centric applications that utilize CKEditor, are also vulnerable.
Mitigation & Remediation
Organizations should patch CKEditor to version 4.16 or later to eliminate the vulnerability. If immediate patching is not feasible, consider implementing input validation to sanitize user inputs in the affected dialog fields. Additionally, continuously monitor systems for unusual behavior that may indicate exploitation attempts.
For more information on securing your applications, organizations can explore options for application security assessments to identify similar weaknesses.
Detection Guidance
To detect potential exploitation attempts, organizations should monitor logs for unusual patterns, particularly in user input fields. Behavioral anomalies such as unexpected spikes in resource consumption, particularly in CKEditor instances, should also be closely analyzed.
AppSecure Threat Intelligence Insight
The long-term significance of CVE-2021-26271 lies in its representation of vulnerabilities in widely used web components. Regularly updating and validating third-party components is crucial to maintaining secure web applications. Security teams should consider adopting a proactive approach to vulnerability management, as this can prevent similar vulnerabilities in the future.
For further insights on security best practices, organizations can refer to our guide on web security and consider implementing a penetration testing methodology that includes regular assessments.
By prioritizing security and staying informed about vulnerabilities like CVE-2021-26271, organizations can better protect their assets and maintain trust with users.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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