CVE-2026-6691
HIGHDescription
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.
How to fix
Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.
CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Exploit Intelligence
Low risk: more likely to be exploited than 3% of all known CVEs.
References
Related Vulnerabilities
Other CWE-120 (Classic Buffer Overflow) vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2014-0195 | Medium | 6.8 | 100% | - | Fix |
| CVE-2017-7269 | Critical | 9.8 | 100% | KEV | - |
| CVE-2019-11043 | High | 8.7 | 99% | KEV + Ransom | Fix |
| CVE-2011-4862 | High | 10.0 | 95% | - | Fix |
| CVE-2007-5659 | High | 7.8 | 94% | KEV | Fix |
| CVE-2022-3786 | High | 7.5 | 91% | - | Fix |
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Markdown
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Start freeThis product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-06-18.