Vulnerability in OpenSSH (CVE-2021-28041)
Summary
Vulnerability in OpenSSH (CVE-2021-28041). Successful exploitation can lead to full system takeover.
Original description
The description as published by the source.
ssh-agent in OpenSSH before 8.5 has a double free that may be relevant in a few less-common scenarios, such as unconstrained agent-socket access on a legacy operating system, or the forwarding of an agent to an attacker-controlled host.
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-2021-28041 has been found in OpenSSH.
Successful exploitation can lead to full system takeover. CVSS score: 7.1/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "OpenSSH CVE-2021-28041" on the vendor's site.
CVE-2021-28041 (OpenSSH) — CWE-415 / CVSS v3 7.1
Attack vector: remote (network-reachable)
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.
A vulnerability (CWE-415) exists in OpenSSH.
Check the vendor advisory for the affected versions of OpenSSH.
Severity: High (CVSS 7.1/10). Successful exploitation can lead to full system takeover.
Update to the patched release per vendor advisory.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'OpenSSH' . 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
-
1Identify exposure identify
grep -r 'OpenSSH' . | 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
OpenSSHを grep し、稼働しているサービス・バージョンを把握する。 -
2Post-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
- Alpine Linux ALPINE-CVE-2021-28041 openssh Fixed in: 8.3_p1-r2
- Debian DEBIAN-CVE-2021-28041 openssh Fixed in: 1:8.4p1-5
References
- advisory security.gentoo.org
- advisory security.netapp.com
- advisory oracle.com
- patch openssh.com
- patch openssh.com
- patch github.com
- patch openwall.com
- web lists.fedoraproject.org
- web lists.fedoraproject.org
- web nvd.nist.gov
- web cert-portal.siemens.com
- web lists.fedoraproject.org
- web lists.fedoraproject.org
- web lists.fedoraproject.org
- web lists.fedoraproject.org
- web security.netapp.com
- web github.com