CVE-2026-6691

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Source
https://cve.org/CVERecord?id=CVE-2026-6691
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-6691.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2026-6691
Downstream
Published
2026-05-06T15:08:23.671Z
Modified
2026-07-08T08:11:37.186958467Z
Severity
  • 8.6 (High) CVSS_V4 - 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 CVSS Calculator
Summary
MongoDB C Driver Cyrus SASL Canonicalization Buffer Overflow
Details

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.

Database specific 
{
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/6xxx/CVE-2026-6691.json",
    "cna_assigner": "mongodb",
    "cwe_ids": [
        "CWE-120"
    ],
    "unresolved_ranges": [
        {
            "source": "AFFECTED_FIELD",
            "extracted_events": [
                {
                    "introduced": "2.1.0"
                },
                {
                    "last_affected": "2.1.2"
                }
            ]
        }
    ]
}
References

Affected packages

Git / github.com/mongodb/mongo-c-driver

Affected ranges

Type
GIT
Repo
https://github.com/mongodb/mongo-c-driver
Events
Introduced
163250d2cc81c532a6315f6ad7e01bf35da9401d
Fixed
81c27ddadd54e80d9743dee0e8b7a0a862aa6ab5
Database specific 
{
    "cpe": "cpe:2.3:a:mongodb:c_driver:*:*:*:*:*:mongodb:*:*",
    "extracted_events": [
        {
            "introduced": "2.1.0"
        },
        {
            "fixed": "2.1.2"
        }
    ],
    "source": "CPE_RANGE"
}

Affected versions

2.*
2.1.0
2.1.1

Database specific

source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-6691.json"