Vulnerability in Cyrus IMAP (CVE-2021-33582)

Summary

Vulnerability in Cyrus IMAP (CVE-2021-33582). Risk of unauthorized operations or information disclosure. Mitigation: upgrade to 3.4.2 or later.

Original description

The description as published by the source.

Cyrus IMAP before 3.4.2 allows remote attackers to cause a denial of service (multiple-minute daemon hang) via input that is mishandled during hash-table interaction. Because there are many insertions into a single bucket, strcmp becomes slow. This is fixed in 3.4.2, 3.2.8, and 3.0.16.

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-2021-33582 has been found in Cyrus IMAP.
Risk of unauthorized operations or information disclosure.
What to do: upgrade Cyrus IMAP to 3.4.2 or later.
If unsure, ask your IT team or search "Cyrus IMAP CVE-2021-33582" on the vendor's site.

CVE-2021-33582 (Cyrus IMAP)
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Patched: 3.4.2 — apply immediately
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 Cyrus IMAP.

📍 Affected scope

Check the vendor advisory for the affected versions of Cyrus IMAP.

🔥 Severity

Severity: ?. Risk of unauthorized operations or information disclosure.

🔧 How to fix

Update to 3.4.2.

🛡️ 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. Audit SBOM/dependencies to find affected services.

Response actions

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

1
Identify exposure identify
```
Audit SBOM/dependencies for affected components.
```
資産台帳・SBOM・依存マニフェストで Cyrus IMAP を使っているサービスとバージョンを洗い出す。
2
Apply patch patch
```
Upgrade Cyrus IMAP to 3.4.2
```
ステージング環境で 3.4.2 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
3
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。

Fix status by distribution

Fixed packages published by each distribution for this CVE

Debian DEBIAN-CVE-2021-33582 cyrus-imapd Fixed in: 3.4.2-1