CVE-2026-6691

HIGH EPSS 2.7%
Published May 6, 20261mo ago · Modified Jun 18, 20261w ago
8.6 CVSS 4.0
High
Find Similar
Published May 6, 2026 1mo ago
Last Modified Jun 18, 2026 1w ago

Description

The MongoDB C Driver's Cyrus SASL integration performs unsafe string copying during username canonicalization, enabling a heap buffer overflow before any authentication or network traffic. This may be triggered by passing untrusted input in the username of a MongoDB URI with authMechanism=GSSAPI.

CVSS Details

Base Score
8.6
Exploitability
—
Impact
—
Vector string
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/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
Attack Vector Local
Attack Complexity Low
Privileges Required None
User Interaction None
Scope X

Threat Intelligence

EPSS Exploit Probability
2.7% percentile
Exploit & Patch Status
No Known Exploit
Patch Available

Weaknesses 2

CWE-120
CWE-787 Out-of-bounds Write Memory Safety

Affected Products 1

VendorProductVersionRange
mongodbc_driver*≥2.1.0  –  <2.1.2

References 1

  • jira.mongodb.org https://jira.mongodb.org/browse/CDRIVER-6134
    PatchVendor AdvisoryIssue Tracking

Remediation

  • jira.mongodb.org https://jira.mongodb.org/browse/CDRIVER-6134
    PatchVendor AdvisoryIssue Tracking