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CVE-2026-116631 Mozilla CVE debrief

A vulnerability in Firefox for iOS could allow a malicious web page to open a tel link in a window showing a different website, causing a phone-call prompt to appear as if the site had requested the call. This issue could potentially trick users into making unintended phone calls. Defenders responsible for managing Firefox for iOS installations should assess the exposure of their users and prioritize updating to version 156.1 or later. The vulnerability was fixed in Firefox for iOS 156.1, and further verification is needed to determine the full scope of affected versions and potential impact.

Vendor
Mozilla
Product
Firefox for iOS
CVSS
MEDIUM 5.4
CISA KEV
Not listed in stored evidence
Original CVE published
2026-10-26
Original CVE updated
2026-10-27
Advisory published
2026-10-26
Advisory updated
2026-10-27

Who should care

Defenders responsible for managing Firefox for iOS installations, particularly those with users who may have accessed malicious web pages, should assess the exposure of their users and prioritize updating to version 156.1 or later.

Why it matters

A vulnerability in Firefox for iOS could allow a malicious web page to open a tel link in a window showing a different website, potentially tricking users into making phone calls. Defenders should prioritize verifying the vulnerability status of Firefox for iOS versions prior to 156.1 and assess the exposure of users who may have accessed malicious web pages.

  • Potential for malicious web pages to trick users into making phone calls
  • Need to verify vulnerability status of Firefox for iOS versions prior to 156.1
  • Possible impact on users who accessed malicious web pages

Technical summary

A malicious web page could open a tel link in a window that was showing a different website, causing the phone-call prompt to appear as if that site had requested the call. This vulnerability was fixed in Firefox for iOS 156.1. The issue involves the handling of tel links in Firefox for iOS, which could be exploited by malicious web pages to trick users into making phone calls. Defenders should prioritize verifying the vulnerability status of Firefox for iOS versions prior to 156.1.

Defensive priority

Defenders should prioritize verifying the vulnerability status of Firefox for iOS versions prior to 156.1 and assess the exposure of users who may have accessed malicious web pages.

Recommended defensive actions

  • Verify the vulnerability status of Firefox for iOS versions prior to 156.1
  • Assess the exposure of users who may have accessed malicious web pages
  • Update Firefox for iOS to version 156.1 or later

Evidence notes

The vulnerability was fixed in Firefox for iOS 156.1. The CVE record and NVD entry provide details on the vulnerability, but further verification is needed to determine the full scope of affected versions and potential impact.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-116631 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-116631

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-116631 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-116631

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.