CVE-2026-81524: A weakness in the MongoDB C Driver allows special elements in caller-supplied database and collection name com

Routine

MEDIUM 5.4UPGRADE

CVE-2026-81524 is a medium-severity flaw (CVSS 5.4) affecting c driver. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A weakness in the MongoDB C Driver allows special elements in caller-supplied database and collection name components to pass without sanitization when the driver composes the target namespace for an operation. An application that incorporates untrusted input into these name components can have operations directed at a resource other than the one intended.

Why this priority

No elevated risk signals yet

A fixed release or distro patch exists.

Risk facts

CVSS score	5.4 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.3% (top 81%)
CISA exploited list	No
Weakness	CWE-99
Published	2026-08-27
Last modified	2026-09-29

Publisher (CNA): MongoDB, Inc. · Vendor: mongodb

Last updated 2026-09-29 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-08-27 20:18 UTCPublished CVE record published
2026-09-29 19:17 UTCUpdated Record last modified

mongodb c driver UPGRADE

Affected: >= 1.0.0 and < 2.5.1

Fixed in: 2.5.1

Safe to downgrade to: a release before 1.0.0

1. Check installed version

apt-cache policy c-driver || rpm -q c-driver || c-driver --version

2. UPGRADE to 2.5.1 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade c-driver

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade c-driver

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 1.0.0 (Debian / Ubuntu)

apt-cache madison c-driver sudo apt install c-driver=<VERSION_BEFORE_1.0.0> sudo apt-mark hold c-driver

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list c-driver sudo dnf downgrade c-driver-<VERSION_BEFORE_1.0.0> sudo dnf versionlock add c-driver

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.

Quick answers

How do I fix CVE-2026-81524?

c driver: upgrade to 2.5.1. Exact commands for each OS are on this page.

Is CVE-2026-81524 being exploited?

CVE-2026-81524 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-2026-81524 affect?

CVE-2026-81524 affects c driver. Severity is medium (CVSS 5.4). A weakness in the MongoDB C Driver allows special elements in caller-supplied database and collection name components to pass without sanitization when the driver composes the target namespace for an operation. An application that incorpora

How urgent is CVE-2026-81524?

Priority 24/100. No elevated risk signals yet.

Software pages

MongoDB vulnerabilities

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References

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