Vulnerability in Mozilla Firefox (CVE-2026-100817)
Summary
Vulnerability in Mozilla Firefox (CVE-2026-100817). Risk of unauthorized operations or information disclosure.
Original description
The description as published by the source.
Other issue in the JavaScript: WebAssembly component. This vulnerability was fixed in Firefox 157.
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 weakness called CVE-2026-100817 was discovered in Mozilla Firefox.
Severity is Medium (CVSS 5.4/10). Exploitation requires specific conditions but can cause real harm if successful.
What you should do: update the affected software to the latest version. If unsure, ask your IT team or search the vendor's site for "Mozilla Firefox CVE-2026-100817".
CVE-2026-100817 (Mozilla Firefox). Severity: Medium / CVSSv3 5.4.
Response plan:
- Check the vendor advisory for affected versions and the patched release.
- If a vulnerable version is running in production, schedule maintenance (urgency from KEV/CVSS).
- If no patch yet, mitigate via WAF rule, disabling the affected feature, etc.
- Monitor logs / SIEM for known IOC and PoC signatures of this CVE.
PoCs and fix commits: see the 'References' section, MITRE, and NVD.
A weakness (CVE-2026-100817) in Mozilla Firefox. A serious software flaw has been identified.
Target versions of Mozilla Firefox (see vendor advisory). If running in production, identify exposure immediately.
Severity: Medium (CVSS 5.4/10). Exploitation requires specific conditions but can cause real harm if successful.
Update to the patched release as listed in the vendor advisory.
If a patch is not yet available, consider disabling the affected feature, applying WAF rules, blocking via network ACLs, or isolating the vulnerable version.
Check version information, scan dependencies via SBOM, and monitor SIEM for IOC and PoC signatures related to this CVE.
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影響コンポーネントを特定する。
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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
- patch security@mozilla.org
- patch security@mozilla.org
- web security@mozilla.org
- web nvd.nist.gov
- web mozilla.org
- web mozilla.org
- web github.com