An out-of-bounds read (CWE-125) has been identified in the GNU coreutils program uniq, triggered when the -w (check-chars) option processes multibyte input. The bug arises from a miscalculation of the byte length of characters within the find_field() function, which uses a fixed pointer instead of advancing correctly through the data. As a result, an inflated length value is passed to a memcmp operation, causing reads beyond the intended buffer and potentially exposing adjacent heap memory after a crash.

The vulnerability affects the GNU coreutils suite. All installed copies of coreutils that include the vulnerable uniq implementation and have not yet incorporated the upstream patch are impacted; no specific version range is disclosed.

The CVSS score is 4.6, indicating a low to moderate severity level, and the EPSS score is reported as < 1%, suggesting a very low probability of exploitation. The vulnerability is not listed in the CISA KEV catalog, and the only known exploitation path is through locally crafted input supplied to uniq. The exposure may lead to disclosure of sensitive information residing in adjacent heap memory after a crash, but it does not provide direct control over the system or allow code execution.