Vulnerability in Oracle Xmlsoft (CVE-2021-3537, CVSS 5.9)

Summary

Vulnerability in Oracle Xmlsoft (CVE-2021-3537). Risk of unauthorized operations or information disclosure.

Original description

The description as published by the source.

A vulnerability found in libxml2 in versions before 2.9.11 shows that it did not propagate errors while parsing XML mixed content, causing a NULL dereference. If an untrusted XML document was parsed in recovery mode and post-validated, the flaw could be used to crash the application. The highest threat from this vulnerability is to system availability.

Source: NIST National Vulnerability Database NVD

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-2021-3537 has been found in Oracle Xmlsoft.
Risk of unauthorized operations or information disclosure. CVSS score: 5.9/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Oracle Xmlsoft CVE-2021-3537" on the vendor's site.

CVE-2021-3537 (Oracle Xmlsoft) — CWE-476 / CVSS v3 5.9
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.

❓ What is the problem

A vulnerability (CWE-476) exists in Oracle Xmlsoft.

📍 Affected scope

Check the vendor advisory for the affected versions of Oracle Xmlsoft.

🔥 Severity

Severity: Medium (CVSS 5.9/10). Risk of unauthorized operations or information disclosure.

🔧 How to fix

Update to the patched release per vendor advisory.

🛡️ Workaround

Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.

🔍 Detection

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

1
Identify 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。
2
Post-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-2021-3537 libxml2 Fixed in: 2.9.9-r5
Debian DEBIAN-CVE-2021-3537 libxml2 Fixed in: 2.9.10+dfsg-6.6

Summary

Original description

Auto-generated summary

Response actions

Fix status by distribution

References