Vulnerability in Github (CVE-2021-32638)

Summary

Vulnerability in Github (CVE-2021-32638). Confidential information can be exposed externally. Exploitable via GITHUB_TOKEN.

Original description

The description as published by the source.

Github's CodeQL action is provided to run CodeQL-based code scanning on non-GitHub CI/CD systems and requires a GitHub access token to connect to a GitHub repository. The runner and its documentation previously suggested passing the GitHub token as a command-line parameter to the process instead of reading it from a file, standard input, or an environment variable. This approach made the token visible to other processes on the same machine, for example in the output of the ps command. If the CI system publicly exposes the output of ps, for example by logging the output, then the GitHub access token can be exposed beyond the scope intended. Users of the CodeQL runner on 3rd-party systems, who are passing a GitHub token via the --github-auth flag, are affected. This applies to both GitHub.com and GitHub Enterprise users. Users of the CodeQL Action on GitHub Actions are not affected. The --github-auth flag is now considered insecure and deprecated. The undocumented --external-repository-token flag has been removed. To securely provide a GitHub access token to the CodeQL runner, users should do one of the following instead: Use the --github-auth-stdin flag and pass the token on the command line via standard input OR set the GITHUB_TOKEN environment variable to contain the token, then call the command without passing in the token. The old flag remains present for backwards compatibility with existing workflows. If the user tries to specify an access token using t…

Source: OSV.dev (Open Source Vulnerabilities) NVD GitHub Advisory OSV

Auto-generated summary

Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.

A vulnerability tracked as CVE-2021-32638 has been found in Github.
Attackers can target a specific entry point like GITHUB_TOKEN over the network to misuse the product.
Confidential information can be exposed externally.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Github CVE-2021-32638" on the vendor's site.

CVE-2021-32638 (Github)
Attack vector: local / no user interaction
Attack surface: GITHUB_TOKEN
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.

❓ What is the problem

A vulnerability (unclassified) exists in Github. Attackers reach the vulnerable code path via GITHUB_TOKEN.

📍 Affected scope

Check the vendor advisory for the affected versions of Github. Attack surface: GITHUB_TOKEN.

🔥 Severity

Severity: ?. Confidential information can be exposed externally.

🔧 How to fix

Update to the patched release per vendor advisory.

🛡️ Workaround

Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.

🔍 Detection

Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'Github' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.

Response actions

Concrete steps and command examples for SOC/SRE teams to execute in order

1
Identify exposure identify
```
grep -r 'Github' . | grep -v node_modules
```
リポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で Github を grep し、稼働しているサービス・バージョンを把握する。
2
Post-deployment verification verify
```
Confirm patched version is live in production
```
パッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。

References

advisory github.com
advisory netmeister.org
patch github.com
patch github.com
patch github.com