CVE-2026-81522: A weakness in the MongoDB C++ Driver's handling of caller-supplied namespace identifiers allows special charac

Routine

HIGH 8.1UPGRADE

CVE-2026-81522 is a high-severity flaw (CVSS 8.1) 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's handling of caller-supplied namespace identifiers allows special characters embedded in those identifiers. An application that builds a namespace identifier from untrusted input without validating it may therefore have its operation directed at a different target than intended. This can result in limited unauthorized read and write access to data belonging to another logical tenant of the affected applicatio

Why this priority

High severity

A fixed release or distro patch exists.

Risk facts

CVSS score	8.1 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.5% (top 60%)
CISA exploited list	No
Weakness	CWE-116
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: >= 3.0.0 and < 4.5.2

Fixed in: 4.5.2

Safe to downgrade to: a release before 3.0.0

1. Check installed version

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

2. UPGRADE to 4.5.2 (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 3.0.0 (Debian / Ubuntu)

apt-cache madison c++-driver sudo apt install c++-driver=<VERSION_BEFORE_3.0.0> 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_3.0.0> 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-2026-81522?

c\+\+ driver: upgrade to 4.5.2. Exact commands for each OS are on this page.

Is CVE-2026-81522 being exploited?

CVE-2026-81522 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-2026-81522 affect?

CVE-2026-81522 affects c\+\+ driver. Severity is high (CVSS 8.1). A weakness in the MongoDB C++ Driver's handling of caller-supplied namespace identifiers allows special characters embedded in those identifiers. An application that builds a namespace identifier from untrusted input without validating it m

How urgent is CVE-2026-81522?

Priority 38/100. High severity

Software pages

MongoDB vulnerabilities

Related CVEs

CVE-2026-84966 MEDIUM 5.1 UPGRADE An incorrect numeric type conversion in the BSON document building component of the MongoDB C++ Driver may cau
CVE-2026-88034 HIGH 8.3 UPGRADE Improper neutralization of special elements in data query logic in the GridFS component of the MongoDB C++ Dri
CVE-2026-84970 MEDIUM 6.2 UPGRADE A numeric truncation weakness exists in the JSON parsing component of the MongoDB C++ Driver's BSON library

References

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