Vulnerability in libxml2 (CVE-2026-76781)
Summary
Vulnerability in libxml2 (CVE-2026-76781). Risk of unauthorized operations or information disclosure. Exploitable via nextCatalog.
Original description
The description as published by the source.
A flaw was found in libxml2. A local user or an attacker providing a specially crafted XML catalog can trigger a NULL pointer dereference during XML catalog parsing. This occurs when a nextCatalog element lacks its mandatory catalog attribute, leading to the application crashing and causing a Denial of Service (DoS).
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-2026-76781 has been found in libxml2.
Attackers can target a specific entry point like nextCatalog over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 5.5/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "libxml2 CVE-2026-76781" on the vendor's site.
CVE-2026-76781 (libxml2) — CWE-476 / CVSS v3 5.5
Attack vector: local / unauthenticated
Attack surface: nextCatalog / catalog
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-476) exists in libxml2. Attackers reach the vulnerable code path via nextCatalog without authentication.
Check the vendor advisory for the affected versions of libxml2. Attack surface: nextCatalog / catalog.
Severity: Medium (CVSS 5.5/10). Risk of unauthorized operations or information disclosure.
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 'libxml2' . 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 'libxml2' . | 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
libxml2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-2026-76781 libxml2
- Ubuntu UBUNTU-CVE-2026-76781 libxml2 Fixed in: 2.9.1+dfsg1-3ubuntu4.13+esm13
References
- web access.redhat.com
- web access.redhat.com
- web bugzilla.redhat.com
- web gitlab.gnome.org
- web gitlab.gnome.org
- web nvd.nist.gov
- web github.com