CVE-2026-6791
MediumCVSS 6.6Exploitation Probability (EPSS)
Low risk11th percentile - higher than 11% of all known CVEs
Summary
When expanding paths that begin with a tilde (~) followed by a username, the internal parse_tilde function extracts the username to determine the user's home directory. The implementation allocates memory for this username directly on the stack using the strndupa macro. Because the size of this allocation was determined by the length of the user-supplied input without any bounds checks, passing an excessively long username (e.g., thousands of characters) forces the thread to exhaust its stack space, potentially leading to a stack clash.
Risk Assessment
If an application passes untrusted, attacker-controlled input to the wordexp function, an attacker can trigger a denial of service or potentially achieve arbitrary code execution depending on the context.
Recommendation
Apply the vendor patch that introduces proper length limits for the username. Avoid passing untrusted data to the wordexp function.
Original NVD description (English source)
When expanding paths that begin with a tilde (~) followed by a username, the internal parse_tilde function extracts the username to determine the user's home directory. The implementation allocates memory for this username directly on the stack using the strndupa macro. Because the size of this allocation was determined by the length of the user-supplied input without any bounds checks, passing an excessively long username e.g. thousands of characters, forces the thread to exhaust its stack space. Thus if an application passes untrusted, attacker-controlled input to the wordexp function, an attacker can trigger a stack clash.