CVE Catalog

CVE-2026-94620

CriticalCVSS 9.4
Published: Updated: Translated: NVD NIST

Summary

Classroom 50 prior to version 1.11.0, when running `gh teacher download`, clones each student's assignment repository and then writes autograde artifacts (`result.json` and `results.json`) into the just-cloned working tree. The write followed symlinks, so a student who committed `result.json` or `results.json` as a symlink could redirect the teacher's write to an arbitrary path (e.g. `~/.zshrc`, `~/.ssh/authorized_keys`, a cron file, or an in-clone `.git/hooks/*` file), with attacker-controlled bytes. This is an arbitrary file write leading to code execution as the teacher, whose `gh` token carries `admin:org`, `repo`, and `workflow` across the entire classroom organization.

Risk Assessment

A student can achieve arbitrary code execution on the teacher's workstation and steal a GitHub token with broad administrative privileges over the entire classroom organization, risking compromise of all repositories and workflows.

Recommendation

Update Classroom 50 to version 1.11.0 or later; until then, avoid running `gh teacher download` against untrusted student repositories or run it inside a disposable sandbox with no access to sensitive host files or credentials.

Related vulnerabilities

Original NVD description (English source)

Classroom 50 is a free and open-source tool for managing and grading programming assignments via GitHub. Prior to version 1.11.0, `gh teacher download` clones each student's assignment repository and then writes autograde artifacts (`result.json` and `results.json`) into the just-cloned working tree. The write followed symlinks, so a student who committed `result.json` or `results.json` as a **symlink** (materialized verbatim by `git clone`) could redirect the teacher's write to an arbitrary path — e.g. `~/.zshrc`, `~/.ssh/authorized_keys`, a cron file, or an in-clone `.git/hooks/*` file that git subsequently executes. The written bytes are attacker-controlled (the student's uploaded release asset for `result.json`; student-chosen submit-tag names for `results.json`). This is an arbitrary file write leading to code execution as the teacher, whose `gh` token carries `admin:org`, `repo`, and `workflow` across the entire classroom organization. Version 1.11.0 contains a patch. Some workarounds are available. Avoid running `gh teacher download` against untrusted student repositories, or run it inside a disposable sandbox / container with no access to sensitive host files or credentials. Inspect cloned trees for symlinked, hardlinked, or special (`result.json`/`results.json`) entries before allowing the artifact-refresh step to run.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS