Vulnerability in Oracle Libssh2 (CVE-2019-3856)
Summary
Vulnerability in Oracle Libssh2 (CVE-2019-3856). Successful exploitation can lead to full system takeover.
Original description
The description as published by the source.
An integer overflow flaw, which could lead to an out of bounds write, was discovered in libssh2 before 1.8.1 in the way keyboard prompt requests are parsed. A remote attacker who compromises a SSH server may be able to execute code on the client system when a user connects to the server.
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-2019-3856 has been found in Oracle Libssh2.
Successful exploitation can lead to full system takeover. CVSS score: 8.8/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Oracle Libssh2 CVE-2019-3856" on the vendor's site.
CVE-2019-3856 (Oracle Libssh2) — CWE-190 / CVSS v3 8.8
Attack vector: remote (network-reachable) / 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.
A vulnerability (CWE-190) exists in Oracle Libssh2.
Check the vendor advisory for the affected versions of Oracle Libssh2.
Severity: High (CVSS 8.8/10). 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 'Libssh2' . 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 'Libssh2' . | 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
Libssh2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-2019-3856 libssh2 Fixed in: 1.8.1-r0
References
- advisory security.netapp.com
- web lists.fedoraproject.org
- web lists.opensuse.org
- web lists.opensuse.org
- web access.redhat.com
- web access.redhat.com
- web access.redhat.com
- web access.redhat.com
- web access.redhat.com
- web access.redhat.com
- web lists.debian.org
- web seclists.org
- web debian.org
- web bugzilla.redhat.com
- web libssh2.org
- web oracle.com
- web cert-portal.siemens.com
- web nvd.nist.gov
- web security.netapp.com
- web lists.fedoraproject.org
- web lists.fedoraproject.org
- web github.com