Mozilla Firefox for iOS 160 Fixes Three Security Issues
Tech GuruQuick Answer
Update Firefox for iOS to version 160 through the supported application channel. Confirm managed-device installation, test required browsing and Reader View workflows, and retain version and deployment evidence.
Confirm Scope And Apply The Supported Remediation
What to do now: Identify iOS devices using Firefox, installed app versions, management policy, application owners and update availability. Match the Firefox for iOS application; this advisory does not establish exposure of desktop Firefox, Firefox for Android or the underlying iOS release. Deploy Firefox for iOS 160 through the supported application distribution channel and confirm the installed version on each managed device. Verify application version and startup, test required browsing, Reader View and sign-in workflows, and retain management deployment results.
Last verified: 2026-11-09 UTC. Recheck the authoritative advisory and supported distribution channel before changing production.
Scope And Authority
| Product scope | Firefox for iOS |
|---|---|
| Advisory | MFSA-2026-124 |
| CVEs | CVE-2026-121841, CVE-2026-121842, CVE-2026-121843 |
| Authoritative release date | November 9, 2026; Mozilla supplies a calendar date without a release time. |
| Authority revision date | No later revision is stated. |
| Affected versions | Firefox for iOS installations requiring the Firefox for iOS 160 security fixes. Mozilla does not state a lower affected-version boundary in this advisory. |
| Fixed version | Firefox for iOS 160 |
| CVSS base score | Not provided by the authority |
| CVSS severity | High (Mozilla impact; CVSS severity not provided) |
| Exploitation status | Mozilla does not state exploitation in this advisory.; no exploitation claim is inferred. |
What Changed
Mozilla issued MFSA-2026-124 for two High-impact privilege-escalation issues, including one in Reader View, and a third Moderate-impact issue. Firefox for iOS 160 contains the fixes; the advisory does not provide detailed attack conditions or CVSS scores.
What To Validate Now
- Inventory. Identify iOS devices using Firefox, installed app versions, management policy, application owners and update availability.
- Establish applicability. Match the Firefox for iOS application; this advisory does not establish exposure of desktop Firefox, Firefox for Android or the underlying iOS release.
- Remediate. Deploy Firefox for iOS 160 through the supported application distribution channel and confirm the installed version on each managed device.
- Validate. Verify application version and startup, test required browsing, Reader View and sign-in workflows, and retain management deployment results.
- Retain evidence. Preserve asset and owner identifiers, the applicability decision, before-and-after versions, change approval, installation output, validation results, and any exception or rollback record.
Operational Cautions
Mozilla provides limited technical detail and no universal lower affected-version bound. Do not infer exploit requirements, exploitation status or a CVSS score from the High impact label.
Evidence To Retain
- Exact product, release stream, package or application version, enabled feature, environment, and accountable owner.
- UTC timestamps, authority revision, approved change record, installer or package-manager output, and resulting version.
- Relevant logs and monitoring evidence, test results, exceptions, compensating controls, and rollback decisions.
Related TechGeeks Resources
Authoritative References
Correction policy: If the authority changes affected versions, fixed versions, severity, exploitation information, mitigations, or required action, TechGeeks will update this notice and its verification date.
