# CERT-FR Warns of Firefox iOS Flaws

Published: 2026-11-10 · Severity: routine
Canonical: https://vorant.io/reports/37ccb0c6-e014-501e-bf9f-7a63c8caac53/cert-fr-warns-of-firefox-ios-flaws
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> CERT-FR advisory lists three vulnerabilities in Firefox for iOS before version 160.0 allowing privilege escalation and an unspecified security issue.

Source: cert.cyber.gouv.fr — https://www.cert.cyber.gouv.fr/avis/CERTFR-2026-AVI-1490

## What to check

- Applies to: The 3 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 referencing Mozilla security bulletin mfsa2026-124, detailing three CVEs (CVE-2026-121841, CVE-2026-121842, CVE-2026-121843) affecting Firefox for iOS versions prior to 160.0. The vulnerabilities could allow an attacker to achieve privilege escalation, as well as an additional security issue not specified by the vendor.

No evidence of active exploitation is mentioned in the advisory. Defenders and users should update Firefox for iOS to version 160.0 or later as per Mozilla's official security bulletin to remediate these issues.

## Mentioned in this report

- Vulnerabilities: CVE-2026-121841, CVE-2026-121842, CVE-2026-121843

Source reporting: https://www.cert.cyber.gouv.fr/avis/CERTFR-2026-AVI-1490

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