CVE-2026-22184 is a classic buffer overflow vulnerability (CWE-120) found in the zlib software package, specifically in the untgz utility component of versions up to and including 1.3.1.2. The flaw exists in the TGZfname() function, which copies the archive name provided via argv[] into a fixed-size static global buffer of 1024 bytes using an unbounded strcpy() call. Since strcpy() does not perform bounds checking, supplying an archive name longer than 1024 bytes results in an out-of-bounds write, corrupting adjacent memory. This overflow occurs before any archive parsing or validation, making it exploitable simply by passing a crafted archive name argument. The consequences include memory corruption, which can cause denial of service (crashes) or potentially allow an attacker to execute arbitrary code depending on the system's compiler, build flags, architecture, and memory layout. The vulnerability requires no privileges, authentication, or user interaction, and can be triggered remotely if the untgz utility is exposed to attacker-controlled inputs. The CVSS v4.0 score of 9.3 reflects the high impact on confidentiality, integrity, and availability, combined with the ease of exploitation. No known public exploits are reported yet, but the severity and simplicity of exploitation make this a critical threat. No official patches were listed at the time of reporting, so users must monitor for updates or apply manual mitigations.

For European organizations, this vulnerability poses a significant risk especially to those relying on zlib in their software stacks, embedded systems, or utilities that process TGZ archives. Exploitation can lead to denial of service, disrupting critical services and operations, or enable remote code execution, potentially allowing attackers to gain control over affected systems. This could compromise sensitive data confidentiality and integrity, and impact availability of services. Industries such as finance, healthcare, telecommunications, and government agencies that use zlib-based tools or software are particularly vulnerable. The vulnerability's ease of exploitation without authentication increases the risk of widespread attacks. Additionally, supply chain software that integrates zlib could propagate the risk across multiple organizations. The potential for memory corruption and arbitrary code execution makes this a critical threat that could be leveraged for ransomware deployment, espionage, or sabotage.

Immediate mitigation involves auditing all systems and software that use zlib, particularly the untgz utility, to identify affected versions. Organizations should prioritize upgrading to a fixed version of zlib once released by the vendor. In the absence of an official patch, applying custom patches to replace unsafe strcpy() calls with bounded string copy functions (e.g., strncpy or strlcpy) is recommended. Implement input validation to restrict archive name lengths to within safe limits before processing. Employ runtime protections such as stack canaries, Address Space Layout Randomization (ASLR), and Data Execution Prevention (DEP) to reduce exploitation success. Restrict access to utilities processing TGZ archives to trusted users and environments. Monitor logs for abnormal usage patterns or crashes related to untgz. Incorporate this vulnerability into vulnerability management and incident response plans. For software developers, conduct thorough code reviews and fuzz testing on input handling functions to prevent similar issues.