CVE-2025-32988 is a double-free vulnerability identified in GnuTLS, a widely used open-source library implementing the TLS and SSL protocols. The flaw arises from improper ownership handling in the export logic of Subject Alternative Name (SAN) entries that contain an otherName field. Specifically, if the type-id Object Identifier (OID) within the otherName is invalid or malformed, GnuTLS erroneously invokes asn1_delete_structure() on an ASN.1 node it does not own. This leads to a double-free condition when the parent function or caller subsequently attempts to free the same memory structure again. The vulnerability can be triggered solely through public GnuTLS APIs, without requiring authentication or user interaction. The consequences of exploitation include denial of service (DoS) due to application crashes or potential memory corruption, which could be leveraged for further exploitation depending on the allocator behavior and environment. The vulnerability affects Red Hat Enterprise Linux 10, which bundles GnuTLS, and has a CVSS v3.1 base score of 6.5, indicating a medium severity level. No known exploits are currently reported in the wild. The vulnerability is notable because it involves ASN.1 parsing, a historically complex and error-prone area, and improper memory management can lead to serious stability and security issues in applications relying on GnuTLS for secure communications.

For European organizations, the impact of CVE-2025-32988 can be significant, especially for those relying on Red Hat Enterprise Linux 10 or other Linux distributions that include the vulnerable GnuTLS version. Since GnuTLS is commonly used in server applications, client software, and embedded systems to provide TLS encryption, exploitation could lead to denial of service conditions, causing service outages or degraded availability of critical systems. Memory corruption could also open avenues for remote code execution or privilege escalation, although this is not explicitly confirmed. Organizations in sectors such as finance, healthcare, telecommunications, and government—where secure communications are paramount—may face operational disruptions or increased risk of targeted attacks leveraging this vulnerability. The medium severity rating suggests that while exploitation is not trivial (due to the requirement for a malformed SAN otherName with an invalid OID), the potential for denial of service and memory corruption warrants prompt attention. Additionally, the vulnerability can be triggered remotely without authentication, increasing the attack surface for exposed services using GnuTLS. This could affect VPN gateways, web servers, mail servers, and other TLS-enabled services prevalent in European enterprises.

To mitigate CVE-2025-32988 effectively, European organizations should: 1) Apply vendor-provided patches or updates for GnuTLS and Red Hat Enterprise Linux 10 as soon as they become available, ensuring all systems are running the fixed versions. 2) Conduct an inventory of all systems and applications using GnuTLS to identify vulnerable endpoints, including embedded devices and third-party software. 3) Implement network-level protections such as Web Application Firewalls (WAFs) or Intrusion Prevention Systems (IPS) configured to detect and block malformed TLS handshake attempts that include suspicious SAN otherName fields. 4) Employ strict input validation and sanitization on any interfaces that accept or process certificates or certificate requests to reduce the risk of malformed data triggering the vulnerability. 5) Monitor system logs and network traffic for unusual TLS handshake failures or crashes indicative of exploitation attempts. 6) Where feasible, consider temporary workarounds such as disabling support for certificates with otherName SAN entries until patches are applied. 7) Engage in proactive vulnerability management and penetration testing to verify the effectiveness of mitigations and detect any exploitation attempts early.