PatchTheCVECVE-2026-18703: An issue in MongoDB Server could allow a party with a valid client certificate and a corresponding user accoun
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Routine
MEDIUM 4.2UPGRADEDOWNGRADE
CVE-2026-18703 is a medium-severity flaw (CVSS 4.2) affecting mongodb, mongodb. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
An issue in MongoDB Server could allow a party with a valid client certificate and a corresponding user account to authenticate using a certificate-based authentication method, even when an administrator has configured the server to restrict authentication to other mechanisms. This could allow authentication through a method the administrator intended to disable.
Why this priority
- No elevated risk signals yet
A fixed release or distro patch exists.
Risk facts
| CVSS score | 4.2 (Medium) |
| Attack vector | Network (remote) |
| Attack complexity | High |
| Privileges needed | Low |
| User interaction | None |
| EPSS exploit chance | 0.1% (top 97%) |
| CISA exploited list | No |
| Weakness | CWE-863 |
| Published | 2026-08-11 |
| Last modified | 2026-10-23 |
Publisher (CNA): MongoDB, Inc. · Vendor: mongodb
Am I affected?
Timeline
- Published CVE record published
- Updated Record last modified
mongodb mongodb UPGRADE
Affected: >= 8.2.0 and <= 8.2.12 · >= 8.3.0 and < 8.3.8
Fixed in: 8.3.8
Safe to downgrade to: a release before 8.2.0
1. Check installed version
apt-cache policy mongodb || rpm -q mongodb || mongodb --version
2. UPGRADE to 8.3.8 (Debian / Ubuntu)
sudo apt update && sudo apt install --only-upgrade mongodb
2. UPGRADE (RHEL / Amazon Linux / Fedora)
sudo dnf upgrade mongodb
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 8.2.0 (Debian / Ubuntu)
apt-cache madison mongodb
sudo apt install mongodb=<VERSION_BEFORE_8.2.0>
sudo apt-mark hold mongodb
3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)
dnf --showduplicates list mongodb
sudo dnf downgrade mongodb-<VERSION_BEFORE_8.2.0>
sudo dnf versionlock add mongodb
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.
mongodb mongodb DOWNGRADE
Affected: 9.0.0 alpha0 · 9.0.0 alpha1 · 9.1.0 alpha0
Fixed in: no fixed release known
Safe to downgrade to: a release before 9.0.0
1. Check installed version
apt-cache policy mongodb || rpm -q mongodb || mongodb --version
2. No fixed release: DOWNGRADE to a release before 9.0.0 (Debian / Ubuntu)
apt-cache madison mongodb
sudo apt install mongodb=<VERSION_BEFORE_9.0.0>
sudo apt-mark hold mongodb
2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)
dnf --showduplicates list mongodb
sudo dnf downgrade mongodb-<VERSION_BEFORE_9.0.0>
sudo dnf versionlock add mongodb
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.
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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