CVE-2025-5269

Name: CVE-2025-5269
Creator: NVD / NIST
Published: 2025-05-27T13:15:22.717+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 8.1/10EPSS 0.38%

Last modified Jun 17, 2026

CVE-2025-5269 is a high-severity vulnerability rated 8.1/10 on the CVSS scale. Memory safety bug present in Firefox ESR 128.10, and Thunderbird 128.10. This bug showed evidence of memory corruption and we presume that with enough effort this could have been exploited to run arbitrary code. EPSS estimates a 0.38% chance of exploitation in the next 30 days.

Description

Memory safety bug present in Firefox ESR 128.10, and Thunderbird 128.10. This bug showed evidence of memory corruption and we presume that with enough effort this could have been exploited to run arbitrary code. This vulnerability was fixed in Firefox ESR 128.11 and Thunderbird 128.11.

Metrics

CVSS 3.1

8.1/10

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

EPSS Probability

0.38%

29.5th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-787

Affected Software

Vendor	Product	Versions
Mozilla	Firefox	< 128.11.0
Mozilla	Thunderbird	< 128.11.0

References

Timeline

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

Frequently Asked Questions

What is CVE-2025-5269?

How severe is CVE-2025-5269?

CVE-2025-5269 has a CVSS score of 8.1/10 (HIGH severity). The EPSS model estimates a 0.38% probability of exploitation in the next 30 days.

How do I fix CVE-2025-5269?

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-2025-5269?

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

Scan your code now

Source: NVD / NIST