CVE-2023-25728: The <code>Content-Security-Policy-Report-Only</code> header could allow an attacker to leak a child iframe's u

Q: How do I fix CVE-2023-25728?

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.

Q: Is CVE-2023-25728 being exploited?

CVE-2023-25728 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-2023-25728 affect?

CVE-2023-25728 affects firefox, firefox esr, thunderbird. Severity is medium (CVSS 6.5). The Content-Security-Policy-Report-Only header could allow an attacker to leak a child iframe's unredacted URI when interaction with that iframe triggers a redirect. This vulnerability affects Firefox < 110, Thunderbird < 102.8

Q: How urgent is CVE-2023-25728?

Priority 39/100. CISA SSVC: public proof of concept

Routine

MEDIUM 6.5UPGRADEUPGRADEUPGRADE

CVE-2023-25728 is a medium-severity flaw (CVSS 6.5) affecting firefox, firefox esr, thunderbird. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

The <code>Content-Security-Policy-Report-Only</code> header could allow an attacker to leak a child iframe's unredacted URI when interaction with that iframe triggers a redirect. This vulnerability affects Firefox < 110, Thunderbird < 102.8, and Firefox ESR < 102.8.

Why this priority

CISA SSVC: public proof of concept

A fixed release or distro patch exists.

Risk facts

CVSS score	6.5 (Medium)
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-203
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

2023-06-02 17:15 UTCPublished CVE record published
2026-10-24 13:10 UTCUpdated 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 · sugar-toolkit-gtk3 · FIXED · 0.122-2.fc46 · FEDORA-2026-d11eb2faf0 · source

sudo dnf upgrade --advisory=FEDORA-2026-d11eb2faf0

Fedora ELN · ntpd-rs · FIXED · 1.7.2-3.eln159 · FEDORA-2026-57e4a99310 · source

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

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 22.04 · firefox · NOT AFFECTED

Ubuntu 24.04 · firefox · NOT AFFECTED

Ubuntu 20.04 · thunderbird · FIXED · 1:102.8.0+build2-0ubuntu0.20.04.1

sudo apt update && sudo apt install --only-upgrade thunderbird dpkg --compare-versions "$(dpkg-query -W -f='${Version}' thunderbird)" ge "1:102.8.0+build2-0ubuntu0.20.04.1" && echo PATCHED || echo STILL-VULNERABLE

Ubuntu 22.04 · thunderbird · FIXED · 1:102.8.0+build2-0ubuntu0.22.04.1

sudo apt update && sudo apt install --only-upgrade thunderbird dpkg --compare-versions "$(dpkg-query -W -f='${Version}' thunderbird)" ge "1:102.8.0+build2-0ubuntu0.22.04.1" && echo PATCHED || echo STILL-VULNERABLE

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

Amazon Linux 2 · see advisory · FIXED · ALAS2-2023-1983 · source

sudo yum update --advisory=ALAS2-2023-1983

Public exploits and detection

Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.

Write-up: bugzilla.mozilla.org/show_bug.cgi?id=1790345

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-2023-25728?

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-2023-25728 being exploited?

CVE-2023-25728 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-2023-25728 affect?

CVE-2023-25728 affects firefox, firefox esr, thunderbird. Severity is medium (CVSS 6.5). The <code>Content-Security-Policy-Report-Only</code> header could allow an attacker to leak a child iframe's unredacted URI when interaction with that iframe triggers a redirect. This vulnerability affects Firefox < 110, Thunderbird < 102.8

How urgent is CVE-2023-25728?

Priority 39/100. CISA SSVC: public proof of concept

Software pages

Mozilla Firefox vulnerabilities

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References

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