CVE-2023-26116 identifies a Regular Expression Denial of Service (ReDoS) vulnerability in Angular version 1.2.21, specifically within the angular.copy() utility function. This function relies on a regular expression that is vulnerable to catastrophic backtracking when processing specially crafted large inputs. Catastrophic backtracking occurs when the regex engine spends excessive time trying to match input due to ambiguous or nested quantifiers, leading to high CPU usage and potential denial of service. The vulnerability does not impact confidentiality or integrity but affects availability by causing service slowdowns or outages. Exploitation requires no authentication or user interaction and can be triggered remotely via network access to affected web applications. The CVSS 3.1 score of 5.3 reflects a medium severity, with an attack vector of network (AV:N), low attack complexity (AC:L), no privileges required (PR:N), and no user interaction (UI:N). No known public exploits have been reported, but the vulnerability poses a risk to legacy Angular applications that have not been updated. Since Angular 1.2.21 is an older version, many modern applications may have migrated away, but legacy systems remain at risk. The vulnerability is classified under CWE-1333, which relates to inefficient regular expressions leading to denial of service.

For European organizations, the primary impact of CVE-2023-26116 is the potential for denial of service attacks against web applications using Angular 1.2.21. This can lead to service unavailability, degraded user experience, and potential operational disruptions, especially for public-facing or critical internal applications. While the vulnerability does not compromise data confidentiality or integrity, the availability impact can affect business continuity and customer trust. Organizations in sectors relying on legacy web applications—such as government portals, financial services, and manufacturing—may face increased risk. Additionally, the exploitation could be used as part of a larger attack chain to distract or degrade defenses. The lack of required authentication and user interaction means attackers can exploit this remotely and at scale if the vulnerable application is exposed to the internet. The medium severity rating suggests moderate urgency but should not be ignored, particularly in environments where uptime is critical.

To mitigate CVE-2023-26116, European organizations should: 1) Upgrade Angular from version 1.2.21 to the latest supported version where the vulnerability is patched or no longer present. If upgrading is not immediately feasible, consider applying any available patches or backported fixes. 2) Implement strict input validation and size limits on data passed to angular.copy() or related functions to prevent large, malicious payloads from triggering the regex. 3) Employ Web Application Firewalls (WAFs) with rules designed to detect and block suspicious payloads that could exploit regex vulnerabilities. 4) Monitor application performance metrics and logs for unusual CPU spikes or slowdowns indicative of ReDoS attempts. 5) Conduct code reviews and security testing focusing on regular expression usage in legacy codebases. 6) Educate developers about the risks of inefficient regular expressions and encourage secure coding practices. 7) Isolate legacy applications behind network segmentation to reduce exposure. These steps collectively reduce the risk of exploitation and improve detection and response capabilities.