CVE-2026-81529: Improper neutralization of delimiters in connection-URL construction allows connection-option injection in the MongoDB C# Driver. When an application passes…

PriorityP338high7.1CVSS 3.1

AVNACHPRLUINSCCHILAN

EPSS

0.29%

19.9th percentile

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

2 ranges

Vendor	Product	Version range	Fixed in
mongodb	c_driver	>= 2.0.0 < 3.11.1	3.11.1
mongodb	c_driver	>= 2.10.0 < 3.11.1	3.11.1

CVSS provenance

nvdv3.17.1HIGHCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:L/A:N

nvdv4.07.1HIGHCVSS:4.0/AV:N/AC:H/AT:N/PR:L/UI:N/VC:H/VI:L/VA:N/SC:H/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Stop checking back — get the weekly exploitation signal.

Every Monday: what got weaponized or added to CISA KEV in the last seven days — each CVE cross-linked to its PoC, Nuclei template, and detection rule. Free, one email a week, unsubscribe in one click.