CVE-2026-88026: Improper neutralization of regular-expression metacharacters in the LINQ query translation component of the Mo

Routine

MEDIUM 6.5UPGRADE

CVE-2026-88026 is a medium-severity flaw (CVSS 6.5) affecting c\# driver. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Improper neutralization of regular-expression metacharacters in the LINQ query translation component of the MongoDB C# Driver can cause a caller-supplied character sequence to alter a regular-expression predicate generated by an affected application. An authenticated user who can influence such a value may cause the application to return records beyond those intended by the original filter.

Why this priority

No elevated risk signals yet

A fixed release or distro patch exists.

Risk facts

CVSS score	6.5 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.4% (top 68%)
CISA exploited list	No
Weakness	CWE-943
Published	2026-09-10
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

2026-09-10 18:18 UTCPublished CVE record published
2026-09-29 16:17 UTCUpdated Record last modified

mongodb c\# driver UPGRADE

Affected: >= 2.14.0 and < 3.11.2

Fixed in: 3.11.2

Safe to downgrade to: a release before 2.14.0

1. Check installed version

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

2. UPGRADE to 3.11.2 (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 2.14.0 (Debian / Ubuntu)

apt-cache madison c-driver sudo apt install c-driver=<VERSION_BEFORE_2.14.0> 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_2.14.0> 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-2026-88026?

c\# driver: upgrade to 3.11.2. Exact commands for each OS are on this page.

Is CVE-2026-88026 being exploited?

CVE-2026-88026 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-2026-88026 affect?

CVE-2026-88026 affects c\# driver. Severity is medium (CVSS 6.5). Improper neutralization of regular-expression metacharacters in the LINQ query translation component of the MongoDB C# Driver can cause a caller-supplied character sequence to alter a regular-expression predicate generated by an affected ap

How urgent is CVE-2026-88026?

Priority 31/100. No elevated risk signals yet.

Software pages

MongoDB vulnerabilities

Related CVEs

CVE-2026-81527 MEDIUM 6.5 UPGRADE A NoSQL/expression injection weakness exists in the LINQ-to-aggregation query translation layer of the MongoDB
CVE-2026-81528 MEDIUM 5.4 UPGRADE A MongoDB C# driver document-replacement code path omits the element-name/shape validation that the equivalent
CVE-2026-81529 HIGH 7.1 UPGRADE Improper neutralization of delimiters in connection-URL construction allows connection-option injection in the
CVE-2026-81530 MEDIUM 5.6 UPGRADE A weakness in the client-side encryption configuration surface of the MongoDB C# Driver causes sensitive key-m
CVE-2026-88025 HIGH 8.3 UPGRADE Improper neutralization of special elements in data query logic in the GridFS component of the MongoDB C# Driv

References

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