# CVE-2026-100866: onefetch through 2.28.1 Terminal Escape Sequence Injection

> Attackers can inject terminal escape sequences via repository metadata to manipulate victim terminal output and window titles when running onefetch.

- **Severity:** Medium 4.8 (`CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:L/VA:N/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:** 27 Sep 2026
- **Updated:** 30 Sep 2026
- **Also known as:** GHSA-fp7q-m5xh-3ggj, openSUSE-SU-2026:12085-1

## What is CVE-2026-100866?

CVE-2026-100866 is a medium-severity vulnerability in o2sh onefetch, published on 27 Sep 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

onefetch through 2.28.1 writes repository information field values to the terminal without removing control characters, allowing terminal escape sequence injection. Attackers can embed ANSI/OSC escape sequences in project manifest version and name fields to manipulate terminal output, rewrite window titles, hide text, or trigger emulator-specific behavior when victims run onefetch.

Weakness: CWE-150 (Improper Neutralization of Escape, Meta, or Control Sequences)

## Which versions are affected by CVE-2026-100866?


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `onefetch` | openSUSE:Tumbleweed | All versions | 3.0.0-1.1 |

## How do I fix CVE-2026-100866?

Upgrade to a fixed version.

## Is CVE-2026-100866 being exploited?

There is no known exploitation of CVE-2026-100866 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-100866 and fix it if it is affected.

What it is: CVE-2026-100866 is a medium-severity vulnerability in o2sh onefetch, published on 27 Sep 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: There is no known exploitation of CVE-2026-100866 in the wild and no public exploit code.

Affected product: o2sh onefetch. 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-2026-100866/ (Markdown: https://insights.sbomify.com/CVE-2026-100866/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-100866
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-100866
- OSV: https://osv.dev/vulnerability/CVE-2026-100866

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-100866/
Summaries are generated and may contain mistakes; the official description above is the record.