CVE-2026-106438: An incorrect calculation in Decimal128 string parsing in the MongoDB C Driver can accept certain over-precisio

Routine

MEDIUM 4.0UPGRADE

CVE-2026-106438 is a medium-severity flaw (CVSS 4.0) affecting c driver. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

An incorrect calculation in Decimal128 string parsing in the MongoDB C Driver can accept certain over-precision inputs containing leading zeros instead of rejecting them. This produces a value different from the supplied text. An actor who can provide a decimal string to an embedding application, including through Extended JSON parsing, can cause the application to store or use an incorrect numeric value.

Why this priority

No elevated risk signals yet

A fixed release or distro patch exists.

Risk facts

CVSS score	4.0 (Medium)
Attack vector	Local
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.1% (top 99%)
CISA exploited list	No
Weakness	CWE-682
Published	2026-10-08
Last modified	2026-10-27

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

Last updated 2026-10-27 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-10-08 19:16 UTCPublished CVE record published
2026-10-27 19:49 UTCUpdated Record last modified

mongodb c driver UPGRADE

Affected: >= 1.4.0 and < 1.30.13 · >= 2.0.0 and < 2.5.6

Fixed in: 1.30.13, 2.5.6

Safe to downgrade to: a release before 1.4.0

1. Check installed version

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

2. UPGRADE to 1.30.13 (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 1.4.0 (Debian / Ubuntu)

apt-cache madison c-driver sudo apt install c-driver=<VERSION_BEFORE_1.4.0> 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_1.4.0> 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-2026-106438?

c driver: upgrade to 1.30.13, 2.5.6. Exact commands for each OS are on this page.

Is CVE-2026-106438 being exploited?

CVE-2026-106438 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-2026-106438 affect?

CVE-2026-106438 affects c driver. Severity is medium (CVSS 4.0). An incorrect calculation in Decimal128 string parsing in the MongoDB C Driver can accept certain over-precision inputs containing leading zeros instead of rejecting them. This produces a value different from the supplied text. An actor who

How urgent is CVE-2026-106438?

Priority 14/100. No elevated risk signals yet.

Software pages

MongoDB vulnerabilities

Related CVEs

CVE-2026-106437 MEDIUM 6.2 UPGRADE The BSON buffer-reservation API in the MongoDB C Driver can record a length smaller than the five-byte BSON mi
CVE-2026-6231 MEDIUM 4.3 UPGRADE The bson_validate function may return early on specific inputs and incorrectly report success
CVE-2026-6691 HIGH 7.8 UPGRADE The MongoDB C Driver's Cyrus SASL integration performs unsafe string copying during username canonicalization,
CVE-2026-81524 MEDIUM 5.4 UPGRADE A weakness in the MongoDB C Driver allows special elements in caller-supplied database and collection name com
CVE-2026-84963 MEDIUM 5.3 UPGRADE An incorrect numeric conversion in the JSON parsing component of the MongoDB C Driver's BSON library may cause

References

← Back to latest CVEs