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Fencer Vulns
high 7.6

CVE-2025-1933 json

JIT corruption of WASM i32 return values on 64-bit CPUs

published 2025-03-04 20 mo ago modified 2026-10-05 34 d ago also EUVD-2025-7438

cvss
7.6
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 24%
public exploits
0
none known

Summary

On 64-bit CPUs, when the JIT compiles WASM i32 return values they can pick up bits from left over memory. This can potentially cause them to be treated as a different type. This vulnerability was fixed in Firefox 136, Firefox ESR 115.21, Firefox ESR 128.8, Thunderbird 136, and Thunderbird 128.8.

Patch / fix

  • mozilla firefox 115.21, 128.8, 136
  • mozilla firefox_esr 115.21, 128.8, 136
  • mozilla thunderbird 128.8, 136
  • firefox-esr Debian 12 128.8.0esr-1~deb12u1
  • firefox-esr Debian 14, Debian 13 128.8.0esr-1
  • thunderbird Debian 12 1:128.8.0esr-1~deb12u1
  • thunderbird Debian 14, Debian 13 1:128.8.0esr-1

debian advisories DEBIAN-CVE-2025-1933

  • firefox Ubuntu 20.04 LTS 136.0+build3-0ubuntu0.20.04.1
  • thunderbird Ubuntu 22.04 LTS 1:128.12.0+build1-0ubuntu0.22.04.1

ubuntu advisories UBUNTU-CVE-2025-1933

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • firefox RHEL 8 128.8.0-1.el8_10
  • firefox RHEL 9 128.8.0-1.el9_5
  • firefox-x11 RHEL 9 128.8.0-1.el9_5
  • firefox RHEL 8.2 AUS 128.8.0-1.el8_2
  • firefox RHEL 7 ELS 128.8.0-1.el7_9
  • firefox RHEL 8.6 TUS, RHEL 8.6 E4S, RHEL 8.6 AUS 128.8.0-1.el8_6
  • firefox RHEL 8.4 TUS, RHEL 8.4 E4S, RHEL 8.4 AUS 128.8.0-1.el8_4
  • firefox RHEL 8.8 EUS 128.8.0-1.el8_8

red hat advisories RHSA-2025:2708RHSA-2025:2699RHSA-2025:2485RHSA-2025:2484RHSA-2025:2486RHSA-2025:2480

  • MozillaThunderbird SLE Workstation Extension 15 SP6, SLE Module for Package Hub 15 SP6, openSUSE Leap 15.6 128.8.0-150200.8.203.1
  • MozillaFirefox SLES for SAP 15 SP5, SLES for SAP 15 SP4, SLES for SAP 15 SP3 +11 more 128.8.0-150200.152.173.1
  • MozillaFirefox SLES LTSS Extended Security 12 SP5, SLES 12 SP5-LTSS 128.8.0-112.249.3

suse advisories SUSE-SU-2025:0849-1SUSE-SU-2025:0788-1SUSE-SU-2025:0783-1

  • MozillaFirefox openSUSE Tumbleweed 136.0-1.1
  • MozillaThunderbird openSUSE Tumbleweed 128.8.0-1.1
  • firefox-esr openSUSE Tumbleweed 128.8.0-1.1

opensuse advisories openSUSE-SU-2025:14861-1openSUSE-SU-2025:14853-1openSUSE-SU-2025:14852-1

  • firefox AlmaLinux 8 128.8.0-1.el8_10
  • firefox AlmaLinux 9 128.8.0-1.el9_5
  • firefox-x11 AlmaLinux 9 128.8.0-1.el9_5

almalinux advisories ALSA-2025:2452ALSA-2025:2359

  • firefox Rocky Linux 8 128.8.0-1.el8_10

rocky linux advisories RLSA-2025:2452

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-2025-1933 updated cvss 7.6

firefox: JIT corruption of WASM i32 return values on 64-bit CPUs

  • Red Hat Enterprise Linux 6 firefox
    affected: no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 9 firefox-flatpak-container Red Hat Enterprise Linux 10 firefox, firefox-flatpak-container
    affected: no fix available
  • Red Hat Enterprise Linux AppStream (v. 8) firefox 128.8.0-1.el8_10
    fixed: vendor fix RHSA-2025:2452
  • Red Hat Enterprise Linux AppStream (v. 9) firefox 128.8.0-1.el9_5, firefox-x11 128.8.0-1.el9_5
    fixed: vendor fix RHSA-2025:2359
  • Red Hat Enterprise Linux AppStream AUS (v. 8.2) firefox 128.8.0-1.el8_2
    fixed: vendor fix RHSA-2025:2708
  • Red Hat Enterprise Linux AppStream AUS (v.8.4) firefox 128.8.0-1.el8_4
    fixed: vendor fix RHSA-2025:2484
  • Red Hat Enterprise Linux AppStream AUS (v.8.6) firefox 128.8.0-1.el8_6
    fixed: vendor fix RHSA-2025:2485
  • Red Hat Enterprise Linux AppStream E4S (v.8.4) firefox 128.8.0-1.el8_4
    fixed: vendor fix RHSA-2025:2484
show 8 more
  • Red Hat Enterprise Linux AppStream E4S (v.8.6) firefox 128.8.0-1.el8_6
    fixed: vendor fix RHSA-2025:2485
  • Red Hat Enterprise Linux AppStream E4S (v.9.0) firefox 128.8.0-1.el9_0
    fixed: vendor fix RHSA-2025:2481
  • Red Hat Enterprise Linux AppStream EUS (v.8.8) firefox 128.8.0-1.el8_8
    fixed: vendor fix RHSA-2025:2486
  • Red Hat Enterprise Linux AppStream EUS (v.9.2) firefox 128.8.0-1.el9_2, firefox-x11 128.8.0-1.el9_2
    fixed: vendor fix RHSA-2025:2480
  • Red Hat Enterprise Linux AppStream EUS (v.9.4) firefox 128.8.0-1.el9_4, firefox-x11 128.8.0-1.el9_4
    fixed: vendor fix RHSA-2025:2479
  • Red Hat Enterprise Linux AppStream TUS (v.8.4) firefox 128.8.0-1.el8_4
    fixed: vendor fix RHSA-2025:2484
  • Red Hat Enterprise Linux AppStream TUS (v.8.6) firefox 128.8.0-1.el8_6
    fixed: vendor fix RHSA-2025:2485
  • Red Hat Enterprise Linux Server (v. 7 ELS) firefox 128.8.0-1.el7_9
    fixed: vendor fix RHSA-2025:2699

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
20 mo ago

Exploit prediction

0.32% chance of exploitation in the next 30 days, higher than 24% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CISA ADP 3.1 7.6 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:H
CNA 3.1 7.6 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:H

Affected products

  • Mozilla Firefox
  • Mozilla Thunderbird

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.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.