A stack-based buffer overflow exists in the ftype() routine of GNU Gawk, triggered while processing the extension/readdir.c program file. The overflow can cause the program to crash and, according to the advisory, may also lead to arbitrary code execution, although the feasibility of this has not been confirmed. The weakness is a classic stack buffer overflow, classified as CWE-121.

GNU Gawk versions 5.4.0 and earlier are affected. Users running these versions should verify the installed gawk against the affected range.

The CVSS score of 5.1 places the vulnerability on the moderate side, and the EPSS score of less than 1% indicates a very low probability of exploitation. The vulnerability is not listed in the CISA KEV catalog. Based on the description, the likely attack vector is local or via untrusted input files processed by gawk, as the overflow originates from handling readdir data. Since code execution has not been confirmed, the risk is primarily a denial of service with a potential, but unverified, code execution risk.