Vulnerability in OpenDKIM (CVE-2020-35766)

Summary

Vulnerability in OpenDKIM (CVE-2020-35766). Successful exploitation can lead to full system takeover.

Original description

The description as published by the source.

The test suite in libopendkim in OpenDKIM through 2.10.3 allows local users to gain privileges via a symlink attack against the /tmp/testkeys file (related to t-testdata.h, t-setup.c, and t-cleanup.c). NOTE: this is applicable to persons who choose to engage in the "A number of self-test programs are included here for unit-testing the library" situation.

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-2020-35766 has been found in OpenDKIM.
Successful exploitation can lead to full system takeover.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "OpenDKIM CVE-2020-35766" on the vendor's site.

CVE-2020-35766 (OpenDKIM)
Attack vector: local / unauthenticated
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 OpenDKIM.

📍 Affected scope

Check the vendor advisory for the affected versions of OpenDKIM.

🔥 Severity

Severity: ?. Successful exploitation can lead to full system takeover.

🔧 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 'OpenDKIM' . 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 'OpenDKIM' . | 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 OpenDKIM 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。

Fix status by distribution

Fixed packages published by each distribution for this CVE

Ubuntu UBUNTU-CVE-2020-35766 opendkim

References

patch github.com