Vulnerability in libssh (UBUNTU-CVE-2026-3731)
Summary
Vulnerability in libssh (UBUNTU-CVE-2026-3731). Risk of unauthorized operations or information disclosure. Mitigation: upgrade to 0.6.3-4.3ubuntu0.6+esm5 or later.
Original description
The description as published by the source.
A weakness has been identified in libssh up to 0.11.3. The impacted element is the function sftp_extensions_get_name/sftp_extensions_get_data of the file src/sftp.c of the component SFTP Extension Name Handler. Executing a manipulation of the argument idx can lead to out-of-bounds read. The attack may be performed from remote. Upgrading to version 0.11.4 and 0.12.0 is sufficient to resolve this issue. This patch is called 855a0853ad3abd4a6cd85ce06fce6d8d4c7a0b60. You should upgrade the affected component.
Source: OSV.dev (Open Source Vulnerabilities) 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 UBUNTU-CVE-2026-3731 has been found in libssh.
Risk of unauthorized operations or information disclosure.
What to do: upgrade libssh to 0.6.3-4.3ubuntu0.6+esm5 or later.
If unsure, ask your IT team or search "libssh UBUNTU-CVE-2026-3731" on the vendor's site.
UBUNTU-CVE-2026-3731 (libssh)
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Patched: 0.6.3-4.3ubuntu0.6+esm5 — 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.
A vulnerability (unclassified) exists in libssh.
Check the vendor advisory for the affected versions of libssh.
Severity: ?. Risk of unauthorized operations or information disclosure.
Update to 0.6.3-4.3ubuntu0.6+esm5.
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 'libssh' . 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
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1Identify exposure identify
grep -r 'libssh' . | 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
libsshを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply patch patch
Upgrade libssh to 0.6.3-4.3ubuntu0.6+esm5ステージング環境で 0.6.3-4.3ubuntu0.6+esm5 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。
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3Post-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。
Affected packages
References
- advisory ubuntu.com
- report ubuntu.com
- report cve.org