# CERT-FR Warns of Firefox iOS Flaws

Published: 2026-10-27 · Severity: routine
Canonical: https://vorant.io/reports/4af6bf8b-93eb-5cba-82a1-ec4b151e8d42/cert-fr-warns-of-firefox-ios-flaws
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> CERT-FR advisory details two vulnerabilities in Firefox for iOS before version 156.1 allowing data integrity compromise and security bypass.

Source: cert.cyber.gouv.fr — https://www.cert.cyber.gouv.fr/avis/CERTFR-2026-AVI-1391

## What to check

- Applies to: The 2 CVEs named below. Whether you run an affected version is not assessed: check the versions the source lists.
- Exploitation: No exploitation in the wild and no public exploit is recorded for the CVEs named.

CERT-FR published an advisory covering two vulnerabilities (CVE-2026-116631 and CVE-2026-116632) affecting Mozilla Firefox for iOS versions prior to 156.1. These flaws, documented in Mozilla's security bulletin MFSA2026-117 released October 26, 2026, could allow an attacker to compromise data integrity and bypass security policy mechanisms within the browser.

No evidence of active exploitation is mentioned in the advisory. Affected organizations and users should update Firefox for iOS to version 156.1 or later as referenced in the official Mozilla security bulletin to remediate these issues.

## Mentioned in this report

- Vulnerabilities: CVE-2026-116631, CVE-2026-116632

Source reporting: https://www.cert.cyber.gouv.fr/avis/CERTFR-2026-AVI-1391

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