Vulnerability in Ruby (CVE-2021-32066)

Summary

Vulnerability in Ruby (CVE-2021-32066). Confidential information can be exposed externally.

Original description

The description as published by the source.

An issue was discovered in Ruby through 2.6.7, 2.7.x through 2.7.3, and 3.x through 3.0.1. Net::IMAP does not raise an exception when StartTLS fails with an an unknown response, which might allow man-in-the-middle attackers to bypass the TLS protections by leveraging a network position between the client and the registry to block the StartTLS command, aka a "StartTLS stripping attack."

Source: OSV.dev (Open Source Vulnerabilities) NVD 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-2021-32066 has been found in Ruby.
Confidential information can be exposed externally.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Ruby CVE-2021-32066" on the vendor's site.

CVE-2021-32066 (Ruby)
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
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 Ruby.

📍 Affected scope

Check the vendor advisory for the affected versions of Ruby.

🔥 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 'Ruby' . 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 'Ruby' . | 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 Ruby 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。

Affected packages

Bitnami ruby-min

[{"type":"SEMVER","events":[{"introduced":"2.6.0"},{"fixed":"2.6.8"},{"introduced":"2.7.0"},{"fixed":"2.7.4"},{"introduced":"3.0.0"},{"fixed":"3.0.2"}]}]

Bitnami ruby

[{"type":"SEMVER","events":[{"introduced":"2.6.0"},{"fixed":"2.6.8"},{"introduced":"2.7.0"},{"fixed":"2.7.4"},{"introduced":"3.0.0"},{"fixed":"3.0.2"}]}]

Fix status by distribution

Fixed packages published by each distribution for this CVE

Alpine Linux ALPINE-CVE-2021-32066 ruby Fixed in: 2.6.8-r0
Debian DEBIAN-CVE-2021-32066 jruby Fixed in: 9.3.9.0+ds-1