CVE-2025-5263

Name: CVE-2025-5263
Creator: NVD / NIST
Published: 2025-05-27T13:15:22.1+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 4.3/10EPSS 0.20%

Last modified Jun 17, 2026

CVE-2025-5263 is a medium-severity vulnerability rated 4.3/10 on the CVSS scale. Error handling for script execution was incorrectly isolated from web content, which could have allowed cross-origin leak attacks. This vulnerability was fixed in Firefox 139, Firefox ESR 115.24, Firefox ESR 128.11, Thunderbird 139, and Thunderbird 128.11.. EPSS estimates a 0.20% chance of exploitation in the next 30 days.

Description

Error handling for script execution was incorrectly isolated from web content, which could have allowed cross-origin leak attacks. This vulnerability was fixed in Firefox 139, Firefox ESR 115.24, Firefox ESR 128.11, Thunderbird 139, and Thunderbird 128.11.

Metrics

CVSS 3.1

4.3/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N

EPSS Probability

0.20%

10.3th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-346

Affected Software

Vendor	Product	Versions
Mozilla	Firefox	< 115.24.0
Mozilla	Firefox	< 139.0
Mozilla	Firefox	>= 116.0, < 128.11.0

References

Timeline

Published: May 27, 2025
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2025-5263?

How severe is CVE-2025-5263?

CVE-2025-5263 has a CVSS score of 4.3/10 (MEDIUM severity). The EPSS model estimates a 0.20% probability of exploitation in the next 30 days.

How do I fix CVE-2025-5263?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2025-5263?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST