CVE-2026-68768
Severity CVSS v4.0:
MEDIUM
Type:
CWE-120
Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
Publication date:
22/08/2026
Last modified:
24/08/2026
Description
hashcat contains a heap-based buffer overflow (out-of-bounds write) in the outfile_write() function in src/outfile.c. When assembling output into a fixed-size buffer (HCBUFSIZ_LARGE, ~16 MB), the function sequentially appends the username, separator, hash, and plaintext via memcpy without validating that the accumulated length stays within the buffer capacity. When run with --username --show against a crafted hash file containing an oversized username that nearly fills the buffer, the total assembled output exceeds the buffer, causing a heap buffer overflow that can corrupt memory and crash the process.
Impact
Base Score 4.0
6.90
Severity 4.0
MEDIUM
Base Score 3.x
6.10
Severity 3.x
MEDIUM
References to Advisories, Solutions, and Tools
- https://github.com/hashcat/hashcat
- https://github.com/hashcat/hashcat/blob/v7.1.2/src/outfile.c#L654-L668
- https://github.com/hashcat/hashcat/commit/68f56a2d8712867a8520bf4dcf07f6145c23df89
- https://github.com/hashcat/hashcat/issues/4740
- https://www.vulncheck.com/advisories/hashcat-through-heap-buffer-overflow-in-outfile-write-via-oversized-username
- https://github.com/hashcat/hashcat/issues/4740