# CVE-2026-121843: Mozilla Firefox for iOS privilege escalation

Source: https://junglewise.ai/threats/cve-2026-121843-privilege-escalation-in-firefox-for-ios-this-vulnerability-was  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-11-09. Updated: 2026-11-09  
License: CC BY 4.0 with a link back

CVE-2026-121843 · Severity: info · Published 2026-11-09

Firefox for iOS is a web browser for Apple's mobile devices. A privilege escalation vulnerability allows an attacker with local access or through malicious content to gain elevated permissions on the device. This could lead to unauthorized access to sensitive user data or device functions.

Technologies: [Mozilla Firefox for iOS](https://junglewise.ai/threats/technologies/firefox-for-ios). Vendors: [Mozilla](https://junglewise.ai/threats/vendors/mozilla).

## Quick answers

**Is CVE-2026-121843 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-121843 being exploited in the wild.

**How severe is CVE-2026-121843?** Informational severity, published 9 November 2026.

**Which products and versions are affected?** Mozilla Firefox for iOS before 160.0.

**Is there a fix for CVE-2026-121843?** Yes: fixed in Firefox for iOS 160.0. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-121843 attacked?** It is attacked with local access, in a web application.

**Am I affected by CVE-2026-121843?** Check whether you run Mozilla Firefox for iOS at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- Fixed in Firefox for iOS 160.0

## Technical details

A privilege escalation flaw exists in Firefox for iOS that allows an attacker to elevate their privileges within the application or system context. The vulnerability requires some level of access or user interaction to exploit. Mozilla patched this issue in version 160.0.

## Affected products

- Mozilla Firefox for iOS before 160.0

## Timeline

- 2026-11-09: disclosed
- 2026-11-09: patched: fixed in Firefox for iOS 160.0

## References

- [https://bugzilla.mozilla.org/show_bug.cgi?id=2083030](https://bugzilla.mozilla.org/show_bug.cgi?id=2083030)
- [https://www.mozilla.org/security/advisories/mfsa2026-124/](https://www.mozilla.org/security/advisories/mfsa2026-124/)

## Related threats

- [Mozilla Firefox for iOS privilege escalation in Reader View](https://junglewise.ai/threats/cve-2026-121842-privilege-escalation-in-the-reader-view-component-in-firefox-for)
- [Firefox for iOS information disclosure](https://junglewise.ai/threats/cve-2026-121841-other-issue-in-firefox-for-ios-this-vulnerability-was-fixed-in)
- [Firefox for iOS FaceTime protocol handler spoofing](https://junglewise.ai/threats/cve-2026-116632-a-malicious-web-page-could-insert-arbitrary-text-into-the)
- [Firefox for iOS external protocol handler spoofing via tel link](https://junglewise.ai/threats/cve-2026-116631-a-malicious-web-page-could-open-a-tel-link-in-a-window-that-was)
- [Firefox for iOS XSS via HTML language attribute in Translation Services](https://junglewise.ai/threats/cve-2026-103418-firefox-for-ios-directly-interpolated-the-page-s-html-language)