CVE-2023-4050: In some cases, an untrusted input stream was copied to a stack buffer without checking its size

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HIGH 7.5REMOTEWATCHLISTUPGRADEMITIGATE

CVE-2023-4050 is a high-severity flaw (CVSS 7.5) affecting firefox, debian linux. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

In some cases, an untrusted input stream was copied to a stack buffer without checking its size. This resulted in a potentially exploitable crash which could have led to a sandbox escape. This vulnerability affects Firefox < 116, Firefox ESR < 102.14, and Firefox ESR < 115.1.

Why this priority

High severity
EPSS top 4%: very likely to be exploited
Remotely exploitable, no login, no user action
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	12.6% (top 4%)
CISA exploited list	No
Weakness	CWE-787
Published	2023-08-01
Last modified	2026-10-23

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

Am I affected?

Timeline

2023-08-01 15:15 UTCPublished CVE record published
2026-10-23 23:10 UTCUpdated Record last modified

mozilla firefox UPGRADE

Affected: < 116.0 · >= 102.0 and < 102.14 · >= 115.0 and < 115.1

Fixed in: 102.14, 115.1, 116.0

Safe to downgrade to: a release before 102.0

1. Check installed version

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

2. UPGRADE to 102.14 (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.

3. If no update is available yet, DOWNGRADE to a release before 102.0 (Debian / Ubuntu)

apt-cache madison firefox sudo apt install firefox=<VERSION_BEFORE_102.0> sudo apt-mark hold firefox

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list firefox sudo dnf downgrade firefox-<VERSION_BEFORE_102.0> sudo dnf versionlock add firefox

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

debian debian linux MITIGATE

Affected: 11.0 · 12.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 11.0

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 · python-openslide · FIXED · 1.4.7-1.fc46 · FEDORA-2026-336bea884e · source

sudo dnf upgrade --advisory=FEDORA-2026-336bea884e

Fedora ELN · valgrind · FIXED · 3.28.0-1.eln159 · FEDORA-2026-c593ef1d15 · source

sudo dnf upgrade --advisory=FEDORA-2026-c593ef1d15

Ubuntu 22.04 · firefox · NOT AFFECTED

Ubuntu 20.04 · firefox · FIXED · 116.0+build2-0ubuntu0.20.04.2

sudo apt update && sudo apt install --only-upgrade firefox dpkg --compare-versions "$(dpkg-query -W -f='${Version}' firefox)" ge "116.0+build2-0ubuntu0.20.04.2" && echo PATCHED || echo STILL-VULNERABLE

Ubuntu 24.04 · firefox · NOT AFFECTED

Ubuntu 20.04 · thunderbird · FIXED · 1:102.15.0+build1-0ubuntu0.20.04.1

sudo apt update && sudo apt install --only-upgrade thunderbird dpkg --compare-versions "$(dpkg-query -W -f='${Version}' thunderbird)" ge "1:102.15.0+build1-0ubuntu0.20.04.1" && echo PATCHED || echo STILL-VULNERABLE

Ubuntu 22.04 · thunderbird · FIXED · 1:102.15.0+build1-0ubuntu0.22.04.1

Debian 12 · firefox-esr · FIXED · 102.14.0esr-1~deb12u1

sudo apt update && sudo apt install --only-upgrade firefox-esr dpkg --compare-versions "$(dpkg-query -W -f='${Version}' firefox-esr)" ge "102.14.0esr-1~deb12u1" && echo PATCHED || echo STILL-VULNERABLE

Debian 13 · firefox-esr · FIXED · 115.1.0esr-1

sudo apt update && sudo apt install --only-upgrade firefox-esr dpkg --compare-versions "$(dpkg-query -W -f='${Version}' firefox-esr)" ge "115.1.0esr-1" && echo PATCHED || echo STILL-VULNERABLE

Debian 12 · thunderbird · FIXED · 1:102.14.0-1~deb12u1

sudo apt update && sudo apt install --only-upgrade thunderbird dpkg --compare-versions "$(dpkg-query -W -f='${Version}' thunderbird)" ge "1:102.14.0-1~deb12u1" && echo PATCHED || echo STILL-VULNERABLE

Debian 13 · thunderbird · FIXED · 1:115.1.0-1

sudo apt update && sudo apt install --only-upgrade thunderbird dpkg --compare-versions "$(dpkg-query -W -f='${Version}' thunderbird)" ge "1:115.1.0-1" && echo PATCHED || echo STILL-VULNERABLE

RHEL 7 · firefox · FIXED · firefox-102.14.0-1.el7_9

sudo dnf upgrade --advisory=RHSA-2023:4461 rpm -q firefox

RHEL 7 · thunderbird · FIXED · thunderbird-102.14.0-1.el7_9

sudo dnf upgrade --advisory=RHSA-2023:4495 rpm -q thunderbird

RHEL 8 · firefox · FIXED · firefox-102.14.0-1.el8_8

sudo dnf upgrade --advisory=RHSA-2023:4468 rpm -q firefox

RHEL 8 · thunderbird · FIXED · thunderbird-102.14.0-1.el8_8

sudo dnf upgrade --advisory=RHSA-2023:4497 rpm -q thunderbird

RHEL 8.1 Update Services for SAP Solutions · firefox · FIXED · firefox-102.14.0-1.el8_1

sudo dnf upgrade --advisory=RHSA-2023:4464 rpm -q firefox

Alpine 3.20 · firefox-esr · FIXED · firefox-esr-115.1.0-r0

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

Alpine 3.21 · firefox-esr · FIXED · firefox-esr-115.1.0-r0

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

Alpine 3.22 · firefox-esr · FIXED · firefox-esr-115.1.0-r0

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

Alpine 3.23 · firefox-esr · FIXED · firefox-esr-115.1.0-r0

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

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.

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References

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