CVE-2024-28835 identifies a vulnerability in GnuTLS version 3.8.3, a widely used open-source TLS library, where an uncaught exception can be triggered during certificate chain verification. Specifically, when the "certtool --verify-chain" command processes a specially crafted .pem bundle, it leads to an application crash due to improper handling of input data. This vulnerability does not compromise confidentiality or integrity but causes a denial of service by crashing the certtool process. The CVSS 3.1 score is 5.0 (medium severity), reflecting local attack vector (AV:L), low attack complexity (AC:L), requiring privileges (PR:L) and user interaction (UI:R), with impact limited to availability (A:H). No known exploits have been reported in the wild, indicating limited active exploitation. The flaw arises from insufficient exception handling during certificate verification, which could be exploited by a local user or attacker with limited privileges who can supply malicious certificate bundles to certtool. Since certtool is often used for certificate management and verification in various Linux distributions and embedded systems, this vulnerability could disrupt automated certificate validation workflows or administrative tasks. The absence of a patch link suggests that a fix may be pending or distributed through vendor-specific updates. Organizations relying on GnuTLS 3.8.3 should monitor for updates and consider temporary mitigations.

The primary impact of CVE-2024-28835 is denial of service through application crashes when verifying maliciously crafted certificate bundles. For European organizations, this could disrupt certificate management processes, automated validation pipelines, or security monitoring tools that utilize certtool. While it does not allow data leakage or unauthorized access, the availability impact could affect critical services relying on timely certificate verification, such as VPN gateways, secure web servers, or internal PKI infrastructures. In sectors like finance, healthcare, and government, where certificate validation is integral to secure communications, such disruptions could delay operations or trigger security alerts. The requirement for local privileges and user interaction limits remote exploitation, but insider threats or compromised accounts could leverage this vulnerability. Given the widespread use of GnuTLS in open-source and embedded environments across Europe, the risk of operational impact exists, especially in organizations with limited patch management capabilities or those using older GnuTLS versions.

To mitigate CVE-2024-28835, organizations should first identify all systems running GnuTLS version 3.8.3 and specifically those using the certtool utility for certificate verification. Since no official patch link is provided yet, monitor vendor advisories and update GnuTLS to a patched version as soon as it becomes available. In the interim, restrict access to certtool to trusted administrators only, minimizing the risk of malicious input. Implement input validation or sanitization on certificate bundles before verification to detect malformed or suspicious files. Employ application-level monitoring to detect unexpected certtool crashes and automate alerts for rapid response. Consider isolating certificate verification processes in sandboxed or containerized environments to limit the impact of crashes. Additionally, review and tighten local user permissions to prevent unprivileged users from executing certtool with crafted inputs. Finally, incorporate this vulnerability into incident response plans to quickly address potential denial of service events related to certificate verification.