CVE-2025-32990 is a heap-based buffer overflow vulnerability identified in the GnuTLS software, specifically within the certtool utility's template parsing logic. The flaw is an off-by-one error that occurs when certtool reads certain settings from a template file. This vulnerability allows an attacker to perform an out-of-bounds NULL pointer write on the heap, leading to memory corruption. The corrupted memory state can cause the certtool utility, and potentially the entire system, to crash, resulting in a denial-of-service (DoS) condition. The vulnerability does not require any privileges or user interaction to be exploited, and it can be triggered remotely if an attacker can supply a crafted template file to the certtool utility. The CVSS v3.1 base score is 6.5, reflecting a medium severity level, with the vector indicating network attack vector (AV:N), low attack complexity (AC:L), no privileges required (PR:N), no user interaction (UI:N), unchanged scope (S:U), no confidentiality impact (C:N), limited integrity impact (I:L), and limited availability impact (A:L). This vulnerability affects Red Hat Enterprise Linux 10, which bundles GnuTLS and its certtool utility. Although no known exploits are currently in the wild, the vulnerability's nature suggests that an attacker could cause service disruption or crash critical services relying on certtool, especially in automated certificate management or renewal processes. The heap-based buffer overflow could also potentially be leveraged for further exploitation, though no direct evidence of code execution is indicated in the current description.

For European organizations, the impact of CVE-2025-32990 could be significant in environments where Red Hat Enterprise Linux 10 is deployed, particularly in sectors relying heavily on secure communications and certificate management such as finance, healthcare, government, and telecommunications. The denial-of-service caused by memory corruption in certtool could disrupt automated certificate issuance or renewal workflows, potentially leading to expired certificates and service outages. This could degrade the availability of critical services and impact business continuity. While the vulnerability does not directly compromise confidentiality, the integrity of certificate management processes is affected, which could indirectly undermine trust in secure communications if certificates are not properly managed. The ease of exploitation (no privileges or user interaction required) increases the risk, especially in multi-tenant or cloud environments where attackers might supply malicious templates. European organizations with automated DevOps pipelines or security operations relying on certtool should be particularly vigilant. The lack of known exploits in the wild currently reduces immediate risk but does not eliminate the threat, as proof-of-concept exploits could emerge.

To mitigate CVE-2025-32990, European organizations should prioritize applying patches or updates from Red Hat as soon as they become available. In the absence of patches, organizations should audit and restrict access to the certtool utility and the template files it processes, ensuring only trusted users and processes can supply or modify templates. Implement strict input validation and sanitization on template files to prevent malformed or malicious inputs. Monitoring and alerting for abnormal certtool crashes or service disruptions can provide early warning of exploitation attempts. Organizations should also review and harden automated certificate management workflows to handle failures gracefully and avoid cascading outages. Employing application whitelisting and runtime protections such as heap memory protections (e.g., ASLR, heap canaries) can reduce exploitation success. Finally, conducting internal penetration testing and code reviews focusing on certificate management tools can identify additional weaknesses.