CVE-2026-6691
Title: Heap Buffer Overflow in MongoDB C Driver
Memory Corruption
Proof Of Concept
No public PoC currently indexed for CVE-2026-6691.
CWE Category
CWE-120
Published Date
May 06, 2026
Modified Date
Jun 18, 2026
Exploit Status
Not Found
Score
8.6
CVSS v4.0
Exploit Probability (EPSS)
0.13%
Vulnerability Summary
CVE-2026-6691: 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.
Impacted Vendors
Reference Links
CVSS v4.0
Source Entity
[email protected]
Severity
HIGH
8.6
Attack Vector
LOCAL
Complexity
LOW
Privileges
N/A
Interaction
NONE
Confidentiality
N/A
Integrity
N/A
Availability
N/A
Scope
N/A
RAW VECTOR
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
CVSS v3.1
Source Entity
[email protected]
Severity
HIGH
7.8
Attack Vector
LOCAL
Complexity
LOW
Privileges
N/A
Interaction
REQUIRED
Confidentiality
N/A
Integrity
N/A
Availability
N/A
Scope
UNCHANGED
RAW VECTOR
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Associated Attack Patterns (CAPEC)
Total: PatternsNo specific attack patterns mapped.
Likelihood
Severity
Page /
CVE-2026-6691 Exploits & PoCs (Proof Of Concept)
No public PoCs found in our database for this CVE.
MODIFIED
Vulnerability data updated via NVD.
MODIFIED
Vulnerability data updated via NVD.
MODIFIED
Vulnerability data updated via NVD.
Attack Vector Matrix
Access Vector
LOCAL
Complexity
LOW
Privileges
N/A
Interaction
NONE
CVSS 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
Affected Stack
No specific products linked.