CVE-2026-81529

Connection-option injection via unescaped settings in the canonical MongoDB URL builder

HIGH
7.1
CVSS Score
Published: August 27, 2026 at 06:32 PM UTC
Updated: September 29, 2026 at 07:16 PM UTC
1 product affected across 1 vendorC++ Driver

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Severity
HIGH7.1
Exploit prediction
EPSS 0.3%
SSVC
No known exploit

Description

Improper neutralization of delimiters in connection-URL construction allows connection-option injection in the MongoDB C# Driver. When an application passes untrusted text into the driver's connection-URL builder and round-trips the builder back into a client configuration, the untrusted text is serialized without neutralizing the URL/option delimiters and is then re-parsed as authoritative connection options. A low-privileged user of such an application can thereby introduce or suppress security-relevant connection settings.

Affected

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

2.0.0 ≤ v < 3.11.12.10.0 ≤ v < 3.11.12.0.0
Affected range stops below 3.11.1, 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:

Patch and advisory references

References (2)

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

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

CVSS

7.1HIGHmongodb
Vector?

Quick Info

StatusANALYZED
CWE
CWE-88

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