CVE-2026-81523

Cross-tenant database retargeting via dot/NUL injection in namespace strings in libmongocrypt

MEDIUM
4.4
CVSS Score
Published: August 27, 2026 at 06:32 PM UTC
Updated: September 17, 2026 at 02:13 PM UTC
1 product affected across 1 vendorLibmongocrypt

Using libmongocrypt by MongoDB?

Get instant alerts when new vulnerabilities affect libmongocrypt - before attackers find them.

Real-time alertsTrack your software stackFree plan available
Severity
MEDIUM4.4
Exploit prediction
EPSS 0.1%
SSVC
No known exploit

Description

A missing input-validation issue in MongoDB libmongocrypt's automatic-encryption context setup allows a caller-supplied database identifier to be accepted without sanitization. The resulting impact is limited to incorrect schema selection, which may lead to limited disclosure or modification of information handled by the application.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 1.20.31.0.0 ≤ v < 1.20.31.0.0
Affected range stops below 1.20.3, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (2)

Vendor AdvisoryIssue TrackingPatch
Source: cverecord
https://jira.mongodb.org/browse/MONGOCRYPT-977

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

4.4MEDIUMmongodb
Attack Vector
LOCAL
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
LOW
Integrity
LOW
Availability
NONE
Vector?

Quick Info

StatusANALYZED
CWE
CWE-74

Get alerted

Stop reading CVE feeds looking for your own stack

Track the products you run and VulnTracker tells you when a new CVE affects them — with what is known about fixing it, and nothing about the rest.

Free plan, no card