PatchTheCEVCVE-2023-29542: A newline in a filename could have been used to bypass the file extension security mechanisms that replace mal
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CRITICAL 9.8REMOTEUPGRADEUPGRADEUPGRADE
CVE-2023-29542 is a critical-severity flaw (CVSS 9.8) affecting firefox, firefox esr, thunderbird. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
A newline in a filename could have been used to bypass the file extension security mechanisms that replace malicious file extensions such as .lnk with .download. This could have led to accidental execution of malicious code. *This bug only affects Firefox and Thunderbird on Windows. Other versions of Firefox and Thunderbird are unaffected.* This vulnerability affects Firefox < 112, Firefox ESR < 102.10, and Thunderbird < 102.10.
Why this priority
- Critical severity
- CISA SSVC: automatable with total technical impact
- Remotely exploitable, no login, no user action
A fixed release or distro patch exists.
Risk facts
| CVSS score | 9.8 (Critical) |
| Attack vector | Network (remote) |
| Attack complexity | Low |
| Privileges needed | None |
| User interaction | None |
| EPSS exploit chance | 0.9% (top 39%) |
| CISA exploited list | No |
| Published | 2023-06-19 |
| Last modified | 2026-10-23 |
Publisher (CNA): Mozilla Corporation · Vendor: mozilla
Am I affected?
Timeline
- Published CVE record published
- Updated 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 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 · 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 24.04 · firefox · NOT AFFECTED
Ubuntu 22.04 · thunderbird · NOT AFFECTED
Ubuntu 24.04 · thunderbird · NOT AFFECTED
Debian 12 · firefox-esr · NOT AFFECTED
Debian 13 · firefox-esr · NOT AFFECTED
Debian 12 · thunderbird · NOT AFFECTED
Debian 13 · thunderbird · NOT AFFECTED
RHEL 6 · firefox · NOT AFFECTED
RHEL 6 · thunderbird · NOT AFFECTED
RHEL 7 · firefox · NOT AFFECTED
RHEL 7 · thunderbird · NOT AFFECTED
RHEL 8 · firefox · NOT AFFECTED
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
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=1810793
- Write-up: bugzilla.mozilla.org/show_bug.cgi?id=1815062
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.
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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