PatchTheCVECVE-2023-25739: Module load requests that failed were not being checked as to whether or not they were cancelled causing a use
47
This month
HIGH 8.8UPGRADEUPGRADEUPGRADE
CVE-2023-25739 is a high-severity flaw (CVSS 8.8) affecting firefox, firefox esr, thunderbird. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
Module load requests that failed were not being checked as to whether or not they were cancelled causing a use-after-free in <code>ScriptLoadContext</code>. This vulnerability affects Firefox < 110, Thunderbird < 102.8, and Firefox ESR < 102.8.
Why this priority
- High severity
- CISA SSVC: public proof of concept
A fixed release or distro patch exists.
Risk facts
| CVSS score | 8.8 (High) |
| Attack vector | Network (remote) |
| Attack complexity | Low |
| Privileges needed | None |
| User interaction | Required |
| EPSS exploit chance | 0.7% (top 48%) |
| CISA exploited list | No |
| Weakness | CWE-416 |
| Published | 2023-06-02 |
| Last modified | 2026-10-24 |
Publisher (CNA): Mozilla Corporation · Vendor: mozilla
Last updated 2026-10-24 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Am I affected?
Timeline
- Published CVE record published
- Updated Record last modified
mozilla firefox UPGRADE
Affected: < 110.0
Fixed in: 110.0
Safe to downgrade to: no unaffected older release
1. Check installed version
apt-cache policy firefox || rpm -q firefox || firefox --version
2. UPGRADE to 110.0 (Debian / Ubuntu)
sudo apt update && sudo apt install --only-upgrade firefox
2. UPGRADE (RHEL / Amazon Linux / Fedora)
sudo dnf upgrade firefox
Note
Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.
mozilla firefox esr UPGRADE
Affected: < 102.8
Fixed in: 102.8
Safe to downgrade to: no unaffected older release
1. Check installed version
apt-cache policy firefox-esr || rpm -q firefox-esr || firefox-esr --version
2. UPGRADE to 102.8 (Debian / Ubuntu)
sudo apt update && sudo apt install --only-upgrade firefox-esr
2. UPGRADE (RHEL / Amazon Linux / Fedora)
sudo dnf upgrade firefox-esr
Note
Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.
mozilla thunderbird UPGRADE
Affected: < 102.8
Fixed in: 102.8
Safe to downgrade to: no unaffected older release
1. Check installed version
apt-cache policy thunderbird || rpm -q thunderbird || thunderbird --version
2. UPGRADE to 102.8 (Debian / Ubuntu)
sudo apt update && sudo apt install --only-upgrade thunderbird
2. UPGRADE (RHEL / Amazon Linux / Fedora)
sudo dnf upgrade thunderbird
Note
Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.
Exact fixes by distribution
Fedora 46 · gnome-shell-extension-tiling-assistant · FIXED · 56-1.fc46 · FEDORA-2026-ebf66a5321 · source
sudo dnf upgrade --advisory=FEDORA-2026-ebf66a5321
Ubuntu 22.04 · firefox · NOT AFFECTED
Ubuntu 20.04 · firefox · FIXED · 110.0+build3-0ubuntu0.20.04.1
sudo apt update && sudo apt install --only-upgrade firefox
dpkg --compare-versions "$(dpkg-query -W -f='${Version}' firefox)" ge "110.0+build3-0ubuntu0.20.04.1" && echo PATCHED || echo STILL-VULNERABLE
Ubuntu 24.04 · firefox · NOT AFFECTED
Ubuntu 22.04 · mozjs102 · FIXED · 102.11.0-0ubuntu0.22.04.1
sudo apt update && sudo apt install --only-upgrade mozjs102
dpkg --compare-versions "$(dpkg-query -W -f='${Version}' mozjs102)" ge "102.11.0-0ubuntu0.22.04.1" && echo PATCHED || echo STILL-VULNERABLE
Ubuntu 24.04 · mozjs102 · NOT AFFECTED
Debian 12 · firefox-esr · FIXED · 102.8.0esr-1
sudo apt update && sudo apt install --only-upgrade firefox-esr
dpkg --compare-versions "$(dpkg-query -W -f='${Version}' firefox-esr)" ge "102.8.0esr-1" && echo PATCHED || echo STILL-VULNERABLE
Debian 13 · firefox-esr · FIXED · 102.8.0esr-1
sudo apt update && sudo apt install --only-upgrade firefox-esr
dpkg --compare-versions "$(dpkg-query -W -f='${Version}' firefox-esr)" ge "102.8.0esr-1" && echo PATCHED || echo STILL-VULNERABLE
Debian 12 · thunderbird · FIXED · 1:102.8.0-1
sudo apt update && sudo apt install --only-upgrade thunderbird
dpkg --compare-versions "$(dpkg-query -W -f='${Version}' thunderbird)" ge "1:102.8.0-1" && echo PATCHED || echo STILL-VULNERABLE
Debian 13 · thunderbird · FIXED · 1:102.8.0-1
sudo apt update && sudo apt install --only-upgrade thunderbird
dpkg --compare-versions "$(dpkg-query -W -f='${Version}' thunderbird)" ge "1:102.8.0-1" && echo PATCHED || echo STILL-VULNERABLE
RHEL 7 · firefox · FIXED · firefox-102.8.0-2.el7_9
sudo dnf upgrade --advisory=RHSA-2023:0812
rpm -q firefox
RHEL 7 · thunderbird · FIXED · thunderbird-102.8.0-2.el7_9
sudo dnf upgrade --advisory=RHSA-2023:0817
rpm -q thunderbird
RHEL 8 · firefox · FIXED · firefox-102.8.0-2.el8_7
sudo dnf upgrade --advisory=RHSA-2023:0808
rpm -q firefox
RHEL 8 · thunderbird · FIXED · thunderbird-102.8.0-2.el8_7
sudo dnf upgrade --advisory=RHSA-2023:0821
rpm -q thunderbird
RHEL 8.1 Update Services for SAP Solutions · firefox · FIXED · firefox-102.8.0-2.el8_1
sudo dnf upgrade --advisory=RHSA-2023:0806
rpm -q firefox
Alpine 3.20 · firefox-esr · FIXED · firefox-esr-102.8.0-r0
apk add --upgrade firefox-esr
apk info -v firefox-esr
Alpine 3.21 · firefox-esr · FIXED · firefox-esr-102.8.0-r0
apk add --upgrade firefox-esr
apk info -v firefox-esr
Alpine 3.22 · firefox-esr · FIXED · firefox-esr-102.8.0-r0
apk add --upgrade firefox-esr
apk info -v firefox-esr
Alpine 3.23 · firefox-esr · FIXED · firefox-esr-102.8.0-r0
apk add --upgrade firefox-esr
apk info -v firefox-esr
sudo yum update --advisory=ALAS2-2023-1983
Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Quick answers
How do I fix CVE-2023-25739?
firefox: upgrade to 110.0; firefox esr: upgrade to 102.8; thunderbird: upgrade to 102.8. Exact commands for each OS are on this page.
Is CVE-2023-25739 being exploited?
CVE-2023-25739 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.
What does CVE-2023-25739 affect?
CVE-2023-25739 affects firefox, firefox esr, thunderbird. Severity is high (CVSS 8.8). Module load requests that failed were not being checked as to whether or not they were cancelled causing a use-after-free in <code>ScriptLoadContext</code>. This vulnerability affects Firefox < 110, Thunderbird < 102.8, and Firefox ESR < 10
How urgent is CVE-2023-25739?
Priority 47/100. High severity; CISA SSVC: public proof of concept
Software pages
Mozilla Firefox vulnerabilities
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