CVE-2026-94620

CRITICALCVSS 9.4/10EPSS 0.41%

Last modified

CVE-2026-94620 is a critical-severity vulnerability rated 9.4/10 on the CVSS scale. 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. EPSS estimates a 0.41% chance of exploitation in the next 30 days.

Description

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.

Metrics

Weakness Enumeration

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
foundation50classroom50< 1.11.0

References

Timeline

Published
Last Modified
Status
Deferred

Frequently Asked Questions

What is 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.
How severe is CVE-2026-94620?
CVE-2026-94620 has a CVSS score of 9.4/10 (CRITICAL severity). The EPSS model estimates a 0.41% probability of exploitation in the next 30 days.
How do I fix CVE-2026-94620?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST