CVE-2023-37211: Memory safety bugs present in Firefox 114, Firefox ESR 102.12, and Thunderbird 102.12

Q: How do I fix CVE-2023-37211?

firefox: upgrade to 115.0; firefox esr: upgrade to 102.13; thunderbird: upgrade to 102.13. Exact commands for each OS are on this page.

Q: Is CVE-2023-37211 being exploited?

CVE-2023-37211 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2023-37211 affect?

CVE-2023-37211 affects firefox, firefox esr, thunderbird. Severity is high (CVSS 8.8). Memory safety bugs present in Firefox 114, Firefox ESR 102.12, and Thunderbird 102.12. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary c

Q: How urgent is CVE-2023-37211?

Priority 49/100. High severity; On your watchlist

This month

HIGH 8.8WATCHLISTUPGRADEUPGRADEUPGRADE

CVE-2023-37211 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.

Memory safety bugs present in Firefox 114, Firefox ESR 102.12, and Thunderbird 102.12. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 115, Firefox ESR < 102.13, and Thunderbird < 102.13.

Why this priority

High severity
On your watchlist

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	0.8% (top 45%)
CISA exploited list	No
Weakness	CWE-787
Published	2023-07-05
Last modified	2026-10-24

Publisher (CNA): Mozilla Corporation · Vendor: debian · mozilla

Last updated 2026-10-24 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2023-07-05 10:15 UTCPublished CVE record published
2026-10-24 13:10 UTCUpdated Record last modified

mozilla firefox UPGRADE

Affected: < 115.0

Fixed in: 115.0

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy firefox || rpm -q firefox || firefox --version

2. UPGRADE to 115.0 (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: < 102.13

Fixed in: 102.13

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 102.13 (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: < 102.13

Fixed in: 102.13

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy thunderbird || rpm -q thunderbird || thunderbird --version

2. UPGRADE to 102.13 (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.

debian debian linux MITIGATE

Affected: 10.0 · 11.0 · 12.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 10.0

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

Exact fixes by distribution

A distro patch exists: prefer upgrading over downgrading.

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 · 115.0+build2-0ubuntu0.20.04.3

sudo apt update && sudo apt install --only-upgrade firefox dpkg --compare-versions "$(dpkg-query -W -f='${Version}' firefox)" ge "115.0+build2-0ubuntu0.20.04.3" && echo PATCHED || echo STILL-VULNERABLE

Ubuntu 24.04 · firefox · NOT AFFECTED

Ubuntu 22.04 · mozjs102 · FIXED · 102.13.0-0ubuntu0.22.04.1

sudo apt update && sudo apt install --only-upgrade mozjs102 dpkg --compare-versions "$(dpkg-query -W -f='${Version}' mozjs102)" ge "102.13.0-0ubuntu0.22.04.1" && echo PATCHED || echo STILL-VULNERABLE

Ubuntu 24.04 · mozjs102 · NOT AFFECTED

Debian 12 · firefox-esr · FIXED · 102.13.0esr-1~deb12u1

sudo apt update && sudo apt install --only-upgrade firefox-esr dpkg --compare-versions "$(dpkg-query -W -f='${Version}' firefox-esr)" ge "102.13.0esr-1~deb12u1" && echo PATCHED || echo STILL-VULNERABLE

Debian 13 · firefox-esr · FIXED · 102.13.0esr-1

sudo apt update && sudo apt install --only-upgrade firefox-esr dpkg --compare-versions "$(dpkg-query -W -f='${Version}' firefox-esr)" ge "102.13.0esr-1" && echo PATCHED || echo STILL-VULNERABLE

Debian 12 · thunderbird · FIXED · 1:102.13.0-1~deb12u1

sudo apt update && sudo apt install --only-upgrade thunderbird dpkg --compare-versions "$(dpkg-query -W -f='${Version}' thunderbird)" ge "1:102.13.0-1~deb12u1" && echo PATCHED || echo STILL-VULNERABLE

Debian 13 · thunderbird · FIXED · 1:102.13.0-1

sudo apt update && sudo apt install --only-upgrade thunderbird dpkg --compare-versions "$(dpkg-query -W -f='${Version}' thunderbird)" ge "1:102.13.0-1" && echo PATCHED || echo STILL-VULNERABLE

RHEL 7 · thunderbird · FIXED · thunderbird-102.13.0-2.el7_9

sudo dnf upgrade --advisory=RHSA-2023:4062 rpm -q thunderbird

RHEL 7 · firefox · FIXED · firefox-102.13.0-2.el7_9

sudo dnf upgrade --advisory=RHSA-2023:4079 rpm -q firefox

RHEL 8 · thunderbird · FIXED · thunderbird-102.13.0-2.el8_8

sudo dnf upgrade --advisory=RHSA-2023:4063 rpm -q thunderbird

RHEL 8 · firefox · FIXED · firefox-102.13.0-2.el8_8

sudo dnf upgrade --advisory=RHSA-2023:4076 rpm -q firefox

RHEL 8.1 Update Services for SAP Solutions · thunderbird · FIXED · thunderbird-102.13.0-2.el8_1

sudo dnf upgrade --advisory=RHSA-2023:4065 rpm -q thunderbird

Alpine 3.20 · firefox-esr · FIXED · firefox-esr-115.0-r0

apk add --upgrade firefox-esr apk info -v firefox-esr

Alpine 3.21 · firefox-esr · FIXED · firefox-esr-115.0-r0

apk add --upgrade firefox-esr apk info -v firefox-esr

Alpine 3.22 · firefox-esr · FIXED · firefox-esr-115.0-r0

apk add --upgrade firefox-esr apk info -v firefox-esr

Alpine 3.23 · firefox-esr · FIXED · firefox-esr-115.0-r0

apk add --upgrade firefox-esr apk info -v firefox-esr

Amazon Linux 2 · see advisory · FIXED · ALAS2-2023-2156 · source

sudo yum update --advisory=ALAS2-2023-2156

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.

Quick answers

How do I fix CVE-2023-37211?

firefox: upgrade to 115.0; firefox esr: upgrade to 102.13; thunderbird: upgrade to 102.13. Exact commands for each OS are on this page.

Is CVE-2023-37211 being exploited?

CVE-2023-37211 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-2023-37211 affect?

CVE-2023-37211 affects firefox, firefox esr, thunderbird. Severity is high (CVSS 8.8). Memory safety bugs present in Firefox 114, Firefox ESR 102.12, and Thunderbird 102.12. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary c

How urgent is CVE-2023-37211?

Priority 49/100. High severity; On your watchlist

Software pages

Debian vulnerabilities · Mozilla Firefox vulnerabilities

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References

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