CVE-2026-94620

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.

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.

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.

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.