Buffer overflow in Hashcat
CVE-2026-68768
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.
Vulnerability class: Buffer Overflow
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:H.
EPSS exploit prediction
EPSS: 0.002 (10.1th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 10th percentile — 10.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.001 · newest: 0.002 · change: +0.001
Affected products
Weakness classification (CWE)
References
- github.com/hashcat/hashcat/issues/4740 (issue-tracking)
- github.com/hashcat/hashcat (product)
- github.com/hashcat/hashcat/commit/68f56a2d8712867a8520bf4dcf07f6145c23df89 (patch)
- github.com/hashcat/hashcat/blob/v7.1.2/src/outfile.c (technical-description)
- www.vulncheck.com/advisories/hashcat-through-heap-buffer-overflow-in-outfile-wr… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-68768?
- CVE-2026-68768 is a medium-severity vulnerability in Hashcat, classified under Buffer Copy without Checking Size of Input (Classic Buffer Overflow). CVSS score: 6.1/10. Published 2026-08-22.
- How severe is CVE-2026-68768?
- Medium severity. CVSS v3 base score is 6.1 out of 10.