PatchTheCVECVE-2026-5732: Incorrect boundary conditions, integer overflow in the Graphics: Text component
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HIGH 8.8UPGRADE
CVE-2026-5732 is a high-severity flaw (CVSS 8.8) affecting firefox. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
Incorrect boundary conditions, integer overflow in the Graphics: Text component. This vulnerability was fixed in Firefox 149.0.2, Firefox ESR 140.9.1, Thunderbird 149.0.2, and Thunderbird 140.9.1.
Why this priority
- High severity
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 49%) |
| CISA exploited list | No |
| Weakness | CWE-190 |
| Published | 2026-04-07 |
| 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: < 140.9.1 · < 149.0.2
Fixed in: 140.9.1, 149.0.2
Safe to downgrade to: no unaffected older release
1. Check installed version
apt-cache policy firefox || rpm -q firefox || firefox --version
2. UPGRADE to 140.9.1 (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.
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 24.04 · firefox · NOT AFFECTED
Ubuntu 25.10 · firefox · NOT AFFECTED
Ubuntu 22.04 · thunderbird · NO FIX YET
Ubuntu 24.04 · thunderbird · NOT AFFECTED
Debian 12 · firefox-esr · FIXED · 140.9.1esr-1~deb12u1
sudo apt update && sudo apt install --only-upgrade firefox-esr
dpkg --compare-versions "$(dpkg-query -W -f='${Version}' firefox-esr)" ge "140.9.1esr-1~deb12u1" && echo PATCHED || echo STILL-VULNERABLE
Debian 13 · firefox-esr · FIXED · 140.9.1esr-1~deb13u1
sudo apt update && sudo apt install --only-upgrade firefox-esr
dpkg --compare-versions "$(dpkg-query -W -f='${Version}' firefox-esr)" ge "140.9.1esr-1~deb13u1" && echo PATCHED || echo STILL-VULNERABLE
Debian 12 · thunderbird · FIXED · 1:140.9.1esr-1~deb12u1
sudo apt update && sudo apt install --only-upgrade thunderbird
dpkg --compare-versions "$(dpkg-query -W -f='${Version}' thunderbird)" ge "1:140.9.1esr-1~deb12u1" && echo PATCHED || echo STILL-VULNERABLE
Debian 13 · thunderbird · FIXED · 1:140.9.1esr-1~deb13u1
sudo apt update && sudo apt install --only-upgrade thunderbird
dpkg --compare-versions "$(dpkg-query -W -f='${Version}' thunderbird)" ge "1:140.9.1esr-1~deb13u1" && echo PATCHED || echo STILL-VULNERABLE
RHEL 10 · firefox · FIXED · firefox-140.9.1-1.el10_1
sudo dnf upgrade --advisory=RHSA-2026:7672
rpm -q firefox
RHEL 10 · thunderbird · FIXED · thunderbird-140.9.1-1.el10_1
sudo dnf upgrade --advisory=RHSA-2026:9638
rpm -q thunderbird
RHEL 10.0 Extended Update Support · thunderbird · FIXED · thunderbird-140.9.1-1.el10_0
sudo dnf upgrade --advisory=RHSA-2026:11813
rpm -q thunderbird
RHEL 10.0 Extended Update Support · firefox · FIXED · firefox-140.9.1-1.el10_0
sudo dnf upgrade --advisory=RHSA-2026:13665
rpm -q firefox
RHEL 7 Extended Lifecycle Support · firefox · FIXED · firefox-140.9.1-2.el7_9
sudo dnf upgrade --advisory=RHSA-2026:13977
rpm -q firefox
sudo dnf update --advisory=ALAS2023-2026-1621
sudo yum update --advisory=ALAS2-2026-3271
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-2026-5732?
firefox: upgrade to 140.9.1, 149.0.2. Exact commands for each OS are on this page.
Is CVE-2026-5732 being exploited?
CVE-2026-5732 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-2026-5732 affect?
CVE-2026-5732 affects firefox. Severity is high (CVSS 8.8). Incorrect boundary conditions, integer overflow in the Graphics: Text component. This vulnerability was fixed in Firefox 149.0.2, Firefox ESR 140.9.1, Thunderbird 149.0.2, and Thunderbird 140.9.1.
How urgent is CVE-2026-5732?
Priority 44/100. High severity
Software pages
Mozilla Firefox vulnerabilities
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