Privilege Escalation in Firefox ESR (CVE-2026-100801)
Summary
Vulnerability in Firefox ESR (CVE-2026-100801). Successful exploitation can lead to full system takeover.
Original description
The description as published by the source.
Privilege escalation in the DLL Services component. This vulnerability was fixed in Firefox ESR 153.4, Firefox 157, and Firefox ESR 140.17.
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-2026-100801 has been found in Firefox ESR.
Successful exploitation can lead to full system takeover. CVSS score: 8.8/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Firefox ESR CVE-2026-100801" on the vendor's site.
CVE-2026-100801 (Firefox ESR) — CWE-269 / CVSS v3 8.8
Attack vector: remote (network-reachable) / 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.
A vulnerability (CWE-269) exists in Firefox ESR.
Check the vendor advisory for the affected versions of Firefox ESR.
Severity: High (CVSS 8.8/10). 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. Audit SBOM/dependencies 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
Audit SBOM/dependencies for affected components.資産台帳・SBOM・依存マニフェストで Firefox ESR を使っているサービスとバージョンを洗い出す。
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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。
References
- web bugzilla.mozilla.org
- web security@mozilla.org
- web security@mozilla.org
- web security@mozilla.org
- web security@mozilla.org
- web security@mozilla.org
- web security@mozilla.org
- web nvd.nist.gov
- web mozilla.org
- web mozilla.org
- web mozilla.org
- web mozilla.org
- web mozilla.org
- web mozilla.org
- web github.com