CVE-2023-29539: When handling the filename directive in the Content-Disposition header, the filename would be truncated if the

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HIGH 8.8UPGRADEUPGRADEUPGRADE

CVE-2023-29539 is a high-severity flaw (CVSS 8.8) affecting firefox, firefox esr, firefox mobile. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

When handling the filename directive in the Content-Disposition header, the filename would be truncated if the filename contained a NULL character. This could have led to reflected file download attacks potentially tricking users to install malware. This vulnerability affects Firefox < 112, Focus for Android < 112, Firefox ESR < 102.10, Firefox for Android < 112, and Thunderbird < 102.10.

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 46%)
CISA exploited list	No
Weakness	CWE-476
Published	2023-06-02
Last modified	2026-10-23

Publisher (CNA): Mozilla Corporation · Vendor: mozilla

Am I affected?

Timeline

2023-06-02 17:15 UTCPublished CVE record published
2026-10-23 23:10 UTCUpdated Record last modified

mozilla firefox UPGRADE

Affected: < 112.0

Fixed in: 112.0

Safe to downgrade to: no unaffected older release

1. Check installed version

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

2. UPGRADE to 112.0 (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: < 102.10

Fixed in: 102.10

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 102.10 (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 firefox mobile UPGRADE

Affected: < 112.0

Fixed in: 112.0

Safe to downgrade to: no unaffected older release

1. Check installed version

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

2. UPGRADE to 112.0 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade firefox-mobile

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade firefox-mobile

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

mozilla focus UPGRADE

Affected: < 112.0

Fixed in: 112.0

Safe to downgrade to: no unaffected older release

1. Check installed version

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

2. UPGRADE to 112.0 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade focus

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade focus

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

mozilla thunderbird UPGRADE

Affected: < 102.10

Fixed in: 102.10

Safe to downgrade to: no unaffected older release

1. Check installed version

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

2. UPGRADE to 102.10 (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 · kwin-zones · FIXED · 1.0.13-1.fc46 · FEDORA-2026-95888f332b · source

sudo dnf upgrade --advisory=FEDORA-2026-95888f332b

Fedora ELN · nginx-mod-brotli · FIXED · 1.0.0~rc-16.eln159 · FEDORA-2026-501a6a8273 · source

sudo dnf upgrade --advisory=FEDORA-2026-501a6a8273

Ubuntu 22.04 · firefox · NOT AFFECTED

Ubuntu 20.04 · firefox · FIXED · 112.0+build2-0ubuntu0.20.04.1

sudo apt update && sudo apt install --only-upgrade firefox dpkg --compare-versions "$(dpkg-query -W -f='${Version}' firefox)" ge "112.0+build2-0ubuntu0.20.04.1" && echo PATCHED || echo STILL-VULNERABLE

Ubuntu 24.04 · firefox · NOT AFFECTED

Ubuntu 22.04 · thunderbird · FIXED · 1:102.10.0+build2-0ubuntu0.22.04.1

sudo apt update && sudo apt install --only-upgrade thunderbird dpkg --compare-versions "$(dpkg-query -W -f='${Version}' thunderbird)" ge "1:102.10.0+build2-0ubuntu0.22.04.1" && echo PATCHED || echo STILL-VULNERABLE

Ubuntu 20.04 · thunderbird · FIXED · 1:102.10.0+build2-0ubuntu0.20.04.1

Debian 12 · firefox-esr · FIXED · 102.10.0esr-1

sudo apt update && sudo apt install --only-upgrade firefox-esr dpkg --compare-versions "$(dpkg-query -W -f='${Version}' firefox-esr)" ge "102.10.0esr-1" && echo PATCHED || echo STILL-VULNERABLE

Debian 13 · firefox-esr · FIXED · 102.10.0esr-1

sudo apt update && sudo apt install --only-upgrade firefox-esr dpkg --compare-versions "$(dpkg-query -W -f='${Version}' firefox-esr)" ge "102.10.0esr-1" && echo PATCHED || echo STILL-VULNERABLE

Debian 12 · thunderbird · FIXED · 1:102.10.0-1

sudo apt update && sudo apt install --only-upgrade thunderbird dpkg --compare-versions "$(dpkg-query -W -f='${Version}' thunderbird)" ge "1:102.10.0-1" && echo PATCHED || echo STILL-VULNERABLE

Debian 13 · thunderbird · FIXED · 1:102.10.0-1

sudo apt update && sudo apt install --only-upgrade thunderbird dpkg --compare-versions "$(dpkg-query -W -f='${Version}' thunderbird)" ge "1:102.10.0-1" && echo PATCHED || echo STILL-VULNERABLE

RHEL 7 · firefox · FIXED · firefox-102.10.0-1.el7_9

sudo dnf upgrade --advisory=RHSA-2023:1791 rpm -q firefox

RHEL 7 · thunderbird · FIXED · thunderbird-102.10.0-2.el7_9

sudo dnf upgrade --advisory=RHSA-2023:1806 rpm -q thunderbird

RHEL 8 · firefox · FIXED · firefox-102.10.0-1.el8_7

sudo dnf upgrade --advisory=RHSA-2023:1787 rpm -q firefox

RHEL 8 · thunderbird · FIXED · thunderbird-102.10.0-2.el8_7

sudo dnf upgrade --advisory=RHSA-2023:1802 rpm -q thunderbird

RHEL 8.1 Update Services for SAP Solutions · firefox · FIXED · firefox-102.10.0-1.el8_1

sudo dnf upgrade --advisory=RHSA-2023:1792 rpm -q firefox

Alpine 3.20 · firefox-esr · FIXED · firefox-esr-102.10.0-r0

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

Alpine 3.21 · firefox-esr · FIXED · firefox-esr-102.10.0-r0

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

Alpine 3.22 · firefox-esr · FIXED · firefox-esr-102.10.0-r0

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

Alpine 3.23 · firefox-esr · FIXED · firefox-esr-102.10.0-r0

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

Amazon Linux 2 · see advisory · FIXED · ALAS2-2023-2028 · source

sudo yum update --advisory=ALAS2-2023-2028

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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