CVE-2025-34457 identifies a stack-based buffer overflow vulnerability in the Dire Wolf software, a popular open-source software soundcard AX.25 packet modem/TNC and APRS encoder/decoder used primarily in amateur radio digital communications. The flaw exists in the kiss_rec_byte() function within src/kiss_frame.c, where the software processes KISS frames—a protocol used to encapsulate AX.25 frames. When a crafted KISS frame reaches the maximum allowed frame length (MAX_KISS_LEN), the function appends a terminating FEND byte without reserving adequate space in the stack buffer. This results in an out-of-bounds write, corrupting adjacent stack memory. Subsequently, the call to kiss_unwrap() performs an out-of-bounds read, further exacerbating memory corruption. The corrupted stack memory can cause application crashes or undefined behavior, effectively enabling a denial-of-service (DoS) attack. The vulnerability can be triggered remotely by sending malicious KISS frames, requiring no authentication or user interaction, making exploitation straightforward. Although no known exploits are currently reported in the wild, the high CVSS 8.7 score reflects the significant risk posed by this vulnerability. The issue was resolved in versions following commit 694c954 by correcting buffer size management and ensuring sufficient space for the terminating byte. Due to the specialized nature of Dire Wolf, the impact is mostly limited to organizations and individuals relying on amateur radio digital communications or related infrastructure.

For European organizations, the primary impact of CVE-2025-34457 is the potential disruption of digital amateur radio communications and related services that rely on Dire Wolf. This could affect emergency communication networks, hobbyist groups, and any critical infrastructure using AX.25 protocols for telemetry or remote monitoring. A successful exploitation leads to denial-of-service conditions by crashing the Dire Wolf application, potentially causing loss of communication capabilities. While confidentiality and integrity impacts are minimal, availability is significantly affected. Organizations involved in disaster response, scientific research, or community communication networks using Dire Wolf may experience operational interruptions. The vulnerability's remote, unauthenticated exploitability increases the risk of opportunistic attacks, especially in regions with active amateur radio communities. However, the lack of known exploits in the wild currently limits immediate widespread impact.

European organizations should prioritize upgrading Dire Wolf to versions released after commit 694c954, where the buffer overflow issue is fixed. If immediate upgrading is not feasible, applying patches that ensure proper buffer allocation in kiss_rec_byte() is critical. Network-level filtering can be implemented to block malformed or suspicious KISS frames, although this may require specialized knowledge of the protocol. Monitoring Dire Wolf logs for crashes or unusual behavior can help detect attempted exploitation. Organizations should also segment networks where Dire Wolf operates to limit exposure to untrusted sources. For critical deployments, consider running Dire Wolf instances with reduced privileges and employing operating system-level protections such as stack canaries and address space layout randomization (ASLR) to mitigate exploitation impact. Regularly review and update security policies related to amateur radio digital communications infrastructure.