CVE-2026-6691CWE-120
MongoDB C Driver Cyrus SASL Canonicalization Buffer Overflow
High · published May 6, 2026
What it is
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.
The record
Technical detail
- CVSS v4.0
- 8.6 · HIGH
- 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
- EPSS
- 0.00184 · 7.6th percentile
- Weakness
- CWE-120 · Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
- Published
- 2026-05-06T15:08Z
EPSS history
Timeline