ZeroDay Findings
Sign inSign up

Vulnerabilities

Vulnerability · CVE-2025-4919

An attacker was able to perform an out-of-bounds read or write on a JavaScript object by confusing array index sizes.

Published May 17, 2025 · catalog updated Apr 13, 2026 · An attacker was able

Check if you run it

No confirmed exploitation is on record for CVE-2025-4919. EPSS is 8.67%. Act only if a listed version of An attacker was able is installed.

Severity
High8.8
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
8.67%
Remediation
Advisory link
Affected products
vendor mozilla

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

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • vendor mozillaversion unspecified

How to fix CVE-2025-4919

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2025-4919. EPSS is 8.67%. Act only if a listed version of An attacker was able is installed.

Which versions are affected?

Affected version ranges are not on this record. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

No weakness class is stored. EPSS 8.67%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. May 17, 2025 · EUVD

    Detected

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

  2. Apr 13, 2026 · EUVD

    Updated

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

Sources

  • FIRST EPSSExploitation probabilityCVE-2025-4919

    30-day exploitation probability 8.7%

    first.org
  • EUVDVulnerability recordEUVD-2025-15598

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

    euvd.enisa.europa.eu

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.