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UBUNTU-CVE-2023-29323
Vulnerability in opensmtpd (UBUNTU-CVE-2023-29323)
Summary
vulnerability in opensmtpd (UBUNTU-CVE-2023-29323). Successful exploitation can lead to full system takeover.
AI summary snake-internal / snake-material-v2
A vulnerability tracked as **UBUNTU-CVE-2023-29323** has been found in opensmtpd.
Successful exploitation can lead to full system takeover. CVSS score: ?/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "opensmtpd UBUNTU-CVE-2023-29323" on the vendor's site.
UBUNTU-CVE-2023-29323 (opensmtpd) —
Attack vector: local / 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 opensmtpd.
📍 Affected scope
opensmtpd — .
🔥 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 'opensmtpd' .` against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response Actions (7 steps)
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'opensmtpd' . | 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 `opensmtpd` を grep し、稼働しているサービス・バージョンを把握する。
-
7Post-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 Step 3 と同じログクエリでアラート再発が無いか継続監視。
Affected packages
Ubuntu:Pro:14.04:LTS
opensmtpd
[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}]
Ubuntu:Pro:16.04:LTS
opensmtpd
[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}]
Ubuntu:18.04:LTS
opensmtpd
[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}]
Ubuntu:20.04:LTS
opensmtpd
[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}]
Ubuntu:22.04:LTS
opensmtpd
[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}]
Ubuntu:24.04:LTS
opensmtpd
[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}]
Ubuntu:25.10
opensmtpd
[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}]
Ubuntu:26.04:LTS
opensmtpd
[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}]
References
- report https://ubuntu.com/security/CVE-2023-29323
- report https://ftp.openbsd.org/pub/OpenBSD/patches/7.1/common/024_smtpd.patch.sig
- report https://ftp.openbsd.org/pub/OpenBSD/patches/7.2/common/020_smtpd.patch.sig
- report https://cvsweb.openbsd.org/cgi-bin/cvsweb/src/usr.sbin/smtpd/envelope.c.diff?r1=1.50&r2=1.51&f=h
- report https://cvsweb.openbsd.org/cgi-bin/cvsweb/src/usr.sbin/smtpd/envelope.c.diff?r1=1.50&r2=1.50.4.1&f=h
- report https://github.com/OpenSMTPD/OpenSMTPD/commit/41d0eae481f538956b1f1fbadfb535043454061f
- report https://github.com/OpenSMTPD/OpenSMTPD/blob/41d0eae481f538956b1f1fbadfb535043454061f/usr.sbin/smtpd/envelope.c#L280
- report https://cvsweb.openbsd.org/cgi-bin/cvsweb/src/usr.sbin/smtpd/envelope.c.diff?r1=1.49&r2=1.49.4.1&f=h
- report https://www.cve.org/CVERecord?id=CVE-2023-29323