Out-of-Bounds Write in Gnu Libidn2 (CVE-2019-18224)
Summary
Out-of-bounds write in Gnu Libidn2 (CVE-2019-18224). Successful exploitation can lead to full system takeover.
Original description
The description as published by the source.
idn2_to_ascii_4i in lib/lookup.c in GNU libidn2 before 2.1.1 has a heap-based buffer overflow via a long domain string.
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-2019-18224 has been found in Gnu Libidn2.
Successful exploitation can lead to full system takeover. CVSS score: 9.8/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Gnu Libidn2 CVE-2019-18224" on the vendor's site.
CVE-2019-18224 (Gnu Libidn2) — CWE-787 / CVSS v3 9.8
Attack vector: remote (network-reachable) / unauthenticated / 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.
Out-of-bounds write (CWE-787) exists in Gnu Libidn2.
Check the vendor advisory for the affected versions of Gnu Libidn2.
Severity: Critical (CVSS 9.8/10). 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 'Libidn2' . 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 'Libidn2' . | 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
Libidn2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-2019-18224 libidn2 Fixed in: 2.1.1-r0
References
- web lists.opensuse.org
- web lists.opensuse.org
- web lists.fedoraproject.org
- web lists.fedoraproject.org
- web seclists.org
- web usn.ubuntu.com
- web github.com
- web security.gentoo.org
- web debian.org
- web bugs.chromium.org
- web github.com
- web cert-portal.siemens.com
- web nvd.nist.gov
- web lists.fedoraproject.org
- web lists.fedoraproject.org
- web usn.ubuntu.com
- web github.com