CVE-2023-4045: Offscreen Canvas did not properly track cross-origin tainting, which could have been used to access image data

Q: How urgent is CVE-2023-4045?

Priority 40/100. Remotely exploitable, no login, no user action; On your watchlist

This month

MEDIUM 5.3REMOTEWATCHLISTUPGRADEMITIGATE

CVE-2023-4045 is a medium-severity flaw (CVSS 5.3) affecting firefox, debian linux. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Offscreen Canvas did not properly track cross-origin tainting, which could have been used to access image data from another site in violation of same-origin policy. This vulnerability affects Firefox < 116, Firefox ESR < 102.14, and Firefox ESR < 115.1.

Why this priority

Remotely exploitable, no login, no user action
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	5.3 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.6% (top 52%)
CISA exploited list	No
Weakness	CWE-346
Published	2023-08-01
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

2023-08-01 15:15 UTCPublished CVE record published
2026-10-24 13:10 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 ELN · ntpd-rs · FIXED · 1.7.2-3.eln159 · FEDORA-2026-57e4a99310 · source

sudo dnf upgrade --advisory=FEDORA-2026-57e4a99310

Fedora 46 · moby-engine · FIXED · 29.9.2-2.fc46 · FEDORA-2026-4856be87b3 · source

sudo dnf upgrade --advisory=FEDORA-2026-4856be87b3

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.

Quick answers

How do I fix CVE-2023-4045?

firefox: upgrade to 102.14, 115.1, 116.0; debian linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2023-4045 being exploited?

CVE-2023-4045 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-2023-4045 affect?

CVE-2023-4045 affects firefox, debian linux. Severity is medium (CVSS 5.3). Offscreen Canvas did not properly track cross-origin tainting, which could have been used to access image data from another site in violation of same-origin policy. This vulnerability affects Firefox < 116, Firefox ESR < 102.14, and Firefox

How urgent is CVE-2023-4045?

Priority 40/100. Remotely exploitable, no login, no user action; On your watchlist

Software pages

Debian vulnerabilities · Mozilla Firefox vulnerabilities

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References

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