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No exploitation reportedFix available

CVE-2025-4919

No exploitation reported by the sources we read.

  • Published2025-05-17
  • Fixed in138.0.4 · 128.10.1 · 115.23.1
  • WeaknessCWE-125 · CWE-787

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

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 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.

Timeline

dates in UTC
  1. 2025-05-1722:15CVE publishedNVD

Versions per branch

NVD
Mozilla firefox
BranchAffectedFixed in
138.0< 138.0.4138.0.4
128.10≥ 116.0, < 128.10.1128.10.1
115.23< 115.23.1115.23.1
Mozilla thunderbird
BranchAffectedFixed in
138.0≥ 138.0, < 138.0.2138.0.2
128.10< 128.10.2128.10.2

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Products declared by the CNA2 products

As mozilla, the CNA that assigned this CVE, declared them in the CVE record; versions as written.

  • Mozilla Firefox

    Not affected ≥ 115.23.1, ≤ 115.* · ≥ 128.10.1, ≤ 128.* · ≥ 138.0.4

  • Mozilla Thunderbird

    Not affected ≥ 128.10.2, ≤ 128.* · ≥ 138.0.2

Source: the CNA record (CVE Program), © The MITRE Corporation,CVE Terms of UseCVE recordupdated 2026-04-13

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • firefoxWolfiall versions · fixed in 128.10.1-r0
  • firefoxRocky Linux:10all versions · fixed in 0:128.10.1-1.el10_0
  • firefoxRocky Linux:8all versions · fixed in 0:128.10.1-1.el8_10
  • firefoxRed Hat:rhel_tus:8.8::appstreamall versions · fixed in 0:128.10.1-1.el8_8and 2 other packages
  • firefoxRed Hat:rhel_tus:8.6::appstreamall versions · fixed in 0:128.10.1-1.el8_6and 2 other packages
  • firefoxRed Hat:rhel_eus:9.4::appstreamall versions · fixed in 0:128.10.1-1.el9_4and 3 other packages
  • firefoxRed Hat:rhel_eus:9.2::appstreamall versions · fixed in 0:128.10.1-1.el9_2and 3 other packages
  • firefoxRed Hat:rhel_els:7all versions · fixed in 0:128.10.1-1.el7_9and 1 other package

80 more package ranges on OSV.dev

Vendor advisories

  • CVE-2025-4919 Red Hat Product Security253 products fixed · 8 known affected

    firefox: thunderbird: Out-of-bounds access when optimizing linear sums

    rhel10/firefox-flatpak.src as a component of Red Hat Enterprise Linux 10 · rhel10/thunderbird-flatpak.src as a component of Red Hat Enterprise Linux 10 · firefox as a component of Red Hat Enterprise Linux 6 · +5 more

  • RHSA-2025:8807 Red Hat Product Security11 products fixed

    Red Hat Security Advisory: firefox security update

  • RHSA-2025:8756 Red Hat Product Security13 products fixed

    Red Hat Security Advisory: thunderbird security update

  • RHSA-2025:8645 Red Hat Product Security21 products fixed

    Red Hat Security Advisory: firefox security update

  • RHSA-2025:8642 Red Hat Product Security13 products fixed

    Red Hat Security Advisory: thunderbird security update

  • RHSA-2025:8631 Red Hat Product Security4 products fixed

    Red Hat Security Advisory: thunderbird security update

16 more advisories

Full record on NVD

Fix

  1. Update Mozilla firefox to 138.0.4 · 128.10.1 · 115.23.1
  2. Vendor fix Red Hat Product Security RHSA-2025:8807 · 11 productsFor details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
  3. Workaround from the vendor Red Hat Product Security RHSA-2025:8807 · 11 productsNo mitigation is currently available that meets Red Hat Product Security’s standards for usability, deployment, applicability, or stability.

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof of concept
Metasploit modules
none listed
Metasploit Framework

Sources

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Published
2025-05-17
Last Modified
2026-09-30
NVD status
Modified
GitHub Advisory
GHSA-f333-vhwv-jvmx

Frequently asked questions

What is 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. 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.

Is CVE-2025-4919 actively exploited?

Active exploitation of CVE-2025-4919 has not been confirmed. Its EPSS score was 9.1% on 2026-11-08, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2025-4919?

CVE-2025-4919 has a CVSS v3 base score of 8.8 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H.

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