Use-After-Free in Oracle Xmlsoft (CVE-2021-3516)
Summary
Vulnerability in Oracle Xmlsoft (CVE-2021-3516). Successful exploitation can lead to full system takeover.
Original description
The description as published by the source.
There's a flaw in libxml2's xmllint in versions before 2.9.11. An attacker who is able to submit a crafted file to be processed by xmllint could trigger a use-after-free. The greatest impact of this flaw is to confidentiality, integrity, and availability.
Source: NIST National Vulnerability Database NVD GitHub Advisory
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-2021-3516 has been found in Oracle Xmlsoft.
Successful exploitation can lead to full system takeover. CVSS score: 7.8/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Oracle Xmlsoft CVE-2021-3516" on the vendor's site.
CVE-2021-3516 (Oracle Xmlsoft) — CWE-416 / CVSS v3 7.8
Attack vector: local / 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.
Use-after-free (CWE-416) exists in Oracle Xmlsoft.
Check the vendor advisory for the affected versions of Oracle Xmlsoft.
Severity: High (CVSS 7.8/10). 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 'Xmlsoft' . 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 'Xmlsoft' . | 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
Xmlsoft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
- Debian DEBIAN-CVE-2021-3516 libxml2 Fixed in: 2.9.10+dfsg-6.6
References
- advisory security.netapp.com
- web bugzilla.redhat.com
- web gitlab.gnome.org
- web gitlab.gnome.org
- web lists.debian.org
- web lists.fedoraproject.org
- web lists.fedoraproject.org
- web security.gentoo.org
- web oracle.com
- web cert-portal.siemens.com
- web nvd.nist.gov
- web lists.fedoraproject.org
- web lists.fedoraproject.org
- web lists.fedoraproject.org
- web lists.fedoraproject.org
- web security.netapp.com
- web github.com