# CVE-2026-68768: hashcat through 7.1.2 Heap Buffer Overflow in outfile_write() via Oversized Username

> An attacker can cause a heap buffer overflow in hashcat by providing an oversized username in a crafted hash file, leading to memory corruption or crashes.

- **Severity:** Medium 6.9 (`CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 22 Aug 2026
- **Updated:** 24 Aug 2026
- **Also known as:** DEBIAN-CVE-2026-68768, GHSA-cm34-rh84-36rf, UBUNTU-CVE-2026-68768

## What is CVE-2026-68768?

CVE-2026-68768 is a medium-severity memory corruption vulnerability in hashcat, published on 22 Aug 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

### Official 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.

Weakness: CWE-120 (Buffer Copy without Checking Size of Input)

## Which versions are affected by CVE-2026-68768?


## How do I fix CVE-2026-68768?

Apply the vendor's patch.

## Is CVE-2026-68768 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-68768 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-68768 and fix it if it is affected.

What it is: CVE-2026-68768 is a medium-severity memory corruption vulnerability in hashcat, published on 22 Aug 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-68768 exists.

Affected product: hashcat. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-68768/ (Markdown: https://insights.sbomify.com/CVE-2026-68768/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-68768
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-68768
- OSV: https://osv.dev/vulnerability/CVE-2026-68768

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-68768/
Summaries are generated and may contain mistakes; the official description above is the record.