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PatchSiren cyber security CVE debrief

CVE-2026-13356 Mozilla CVE debrief

A malicious webpage could interrupt a pending navigation by enqueuing a synchronous JavaScript dialog, causing the browser UI to display the destination origin in the address bar while continuing to render attacker-controlled content. This vulnerability was fixed in Firefox for iOS 152.3. The issue allows for user interface deception and rendering of attacker-controlled content, posing a medium priority risk. Users of Firefox for iOS should ensure they are running version 152.3 or later to mitigate this vulnerability.

Vendor
Mozilla
Product
Firefox for iOS
CVSS
MEDIUM 6.3
CISA KEV
Not listed in stored evidence
Original CVE published
2026-07-07
Original CVE updated
2026-07-07
Advisory published
2026-07-07
Advisory updated
2026-07-07

Who should care

Users of Firefox for iOS should ensure they are running version 152.3 or later to mitigate this vulnerability. This vulnerability has a medium priority due to the potential for user interface deception and rendering of attacker-controlled content. Operators, platform administrators, vulnerability management teams, and security teams should review the official advisory and CVE record to validate affected scope, severity, and vendor guidance.

Technical summary

The vulnerability allows a malicious webpage to interrupt a pending navigation by enqueuing a synchronous JavaScript dialog. This causes the browser UI to display the destination origin in the address bar while continuing to render attacker-controlled content. The issue was addressed with the release of Firefox for iOS 152.3. The vulnerability has a CVSS score of 6.3 and a severity of MEDIUM. It is recommended that users update to the latest version to prevent potential exploitation.

Defensive priority

Medium priority due to the potential for user interface deception and rendering of attacker-controlled content.

Recommended defensive actions

  • Update Firefox for iOS to version 152.3 or later
  • Monitor for suspicious web page activity
  • Implement Content Security Policy (CSP) to restrict JavaScript execution
  • Review compensating controls for exposed systems while remediation is scheduled and verified
  • Check relevant monitoring, detection, and logs for exposed assets that need extra review
  • Track exceptions, retest remediated assets, and close the item only after evidence is documented
  • Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The CVE record was published on 2026-07-07T00:16:34.063Z and has not been modified since then. The NVD entry is currently Awaiting Analysis. This information is based on the official CVE record and NVD detail page. Further verification is recommended to confirm affected scope and severity.

Official resources

AI-assisted PatchSiren debrief based on the supplied source corpus. The CVE record was published on 2026-07-07T00:16:34.063Z and has not been modified since then. The NVD entry is currently Awaiting Analysis.