PT-2026-37642 · Mongodb+1 · Mongodb C Driver+1

CVE-2026-6691

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Published

2025-10-22

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Updated

2026-07-28

CVSS v4.0

8.6

High

VectorAV: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
Name of the Vulnerable Software and Affected Versions mongo-c-driver (affected versions not specified)
Description The Cyrus SASL integration in the MongoDB C Driver performs unsafe string copying during username canonicalization. This flaw enables a heap buffer overflow—a condition where data exceeds the allocated memory buffer on the heap—before any authentication or network traffic occurs. The issue can be triggered by providing untrusted input in the username of a MongoDB URI when using the authMechanism=GSSAPI parameter. This may allow a remote attacker to cause a denial of service.
Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.

Exploit

DoS

Buffer Overflow

Memory Corruption

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Weakness Enumeration

Related Identifiers

BDU:2026-12766
CVE-2026-6691
OESA-2026-2690
OESA-2026-2691
OESA-2026-2692
OESA-2026-2693

Affected Products

Red Os
Mongodb C Driver