How severe is CVE-2026-13356?

CVE-2026-13356 has a CVSS 3.x base score of 6.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability low.

Is CVE-2026-13356 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (4th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-13356?

CVE-2026-13356 affects Mozilla Firefox. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-13356?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2026-13356 published?

CVE-2026-13356 was published on 2026-07-07 and last updated on 2026-07-08.

CVE-2026-13356

CVE-2026-13356 is a medium-severity vulnerability in Mozilla Firefox with a CVSS 3.x base score of 6.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-451.

Key facts

Severity: Medium (CVSS 3.x base score 6.3)
EPSS exploit prediction: 0% (4th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-451
Affected product: Mozilla Firefox
Published: 2026-07-07
Last modified: 2026-07-08

Description

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.

Frequently asked questions

What is CVE-2026-13356?: 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.
How severe is CVE-2026-13356?: CVE-2026-13356 has a CVSS 3.x base score of 6.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability low.
Is CVE-2026-13356 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (4th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-13356?: CVE-2026-13356 affects Mozilla Firefox. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-13356?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2026-13356 published?: CVE-2026-13356 was published on 2026-07-07 and last updated on 2026-07-08.

References

Affected products (1)

cpe:2.3:a:mozilla:firefox:*:*:*:*:*:iphone_os:*:*

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