CVE-2025-4919

Description

An attacker was able to perform an out-of-bounds read or write on a JavaScript object by confusing array index sizes. This vulnerability affects Firefox < 138.0.4, Firefox ESR < 128.10.1, Firefox ESR < 115.23.1, Thunderbird < 128.10.2, and Thunderbird < 138.0.2.

Category

8.8
CVSS
Severity: High
CVSS 3.1 •
EPSS 0.04%
Vendor Advisory mozilla.org Vendor Advisory mozilla.org Vendor Advisory mozilla.org Vendor Advisory mozilla.org Vendor Advisory mozilla.org
Affected: Mozilla Firefox
Affected: Mozilla Firefox ESR
Affected: Mozilla Firefox ESR
Affected: Mozilla Thunderbird
Affected: Mozilla Thunderbird
Published at:
Updated at:

References

Link Tags
https://bugzilla.mozilla.org/show_bug.cgi?id=1966614 permissions required
https://www.mozilla.org/security/advisories/mfsa2025-36/ vendor advisory
https://www.mozilla.org/security/advisories/mfsa2025-37/ vendor advisory
https://www.mozilla.org/security/advisories/mfsa2025-38/ vendor advisory
https://www.mozilla.org/security/advisories/mfsa2025-40/ vendor advisory
https://www.mozilla.org/security/advisories/mfsa2025-41/ vendor advisory

Frequently Asked Questions

What is the severity of CVE-2025-4919?
CVE-2025-4919 has been scored as a high severity vulnerability.
How to fix CVE-2025-4919?
To fix CVE-2025-4919, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2025-4919 being actively exploited in the wild?
As for now, there are no information to confirm that CVE-2025-4919 is being actively exploited. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2025-4919?
CVE-2025-4919 affects Mozilla Firefox, Mozilla Firefox ESR, Mozilla Firefox ESR, Mozilla Thunderbird, Mozilla Thunderbird.
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