Skip to content
Fencer Vulns
medium 5.4

CVE-2026-2804 json

Use-after-free in the JavaScript: WebAssembly component

published 2026-02-24 8 mo ago modified 2026-06-17 4 mo ago also EUVD-2026-8457

cvss
5.4
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 40%
public exploits
0
none known

Summary

Use-after-free in the JavaScript: WebAssembly component. This vulnerability was fixed in Firefox 148 and Thunderbird 148.

Patch / fix

  • mozilla firefox 148.0
  • mozilla thunderbird 148.0
  • firefox-esr openSUSE Tumbleweed 153.0-1.1
  • MozillaFirefox openSUSE Tumbleweed 148.0-1.1

opensuse advisories openSUSE-SU-2026:11373-1openSUSE-SU-2026:10257-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-2804 updated cvss 6.1

firefox: thunderbird: Use-after-free in the JavaScript: WebAssembly component

  • Red Hat Enterprise Linux 6 firefox, rhel10/thunderbird-flatpak Red Hat Enterprise Linux 7 firefox, rhel10/thunderbird-flatpak Red Hat Enterprise Linux 8 firefox, rhel10/thunderbird-flatpak Red Hat Enterprise Linux 9 firefox, firefox-x11, rhel10/thunderbird-flatpak Red Hat Enterprise Linux 10 firefox, rhel8/flatpak-runtime, rhel10/firefox-flatpak, rhel10/thunderbird-flatpak
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
8 mo ago

Exploit prediction

0.47% chance of exploitation in the next 30 days, higher than 40% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CISA ADP 3.1 5.4 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N
CNA 3.1 5.4 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N

Affected products

  • Mozilla Firefox
  • Mozilla Thunderbird

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.