CVE-2026-6691MongoDB C Driver Cyrus SASL Canonicalization Buffer Overflow
Updated under an hour ago ()
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It affects MongoDB Inc. MongoDB C Driver. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
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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.
- CVSS
- 7.8 HIGH (v3.1, CNA)CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
- Weakness (CWE)
- CWE-120
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- mongodb
- NVD analysis
- Analyzed
- Record last updated
- May 6, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
MongoDB Inc. MongoDB C Driver mongodb:c_driver (from the name) | from 2.1.0 through 2.1.2 | CNA record |
mongodb c_driver mongodb:c_driver | from 2.1.0 before 2.1.2 | NVD |
References
- https://jira.mongodb.org/browse/CDRIVER-6134patch, vendor-advisory, issue-tracking
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.