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TI-2026-05870 Aliases CVE-2026-6691GHSA-587q-94wg-2pfp

MongoDB C Driver Cyrus SASL Canonicalization Buffer Overflow

Priority LOW 38CWE-120Published · Updated

Key facts

Attack vector
Local
Privileges required
None
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
Code execution
Confidentiality · integrity · availability
High · High · High
Fix status
No fix listed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-120 and the CVSS impact.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00126 2nd percentileScored 2026-11-07
Fix No fix listed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
MongoDBMongoDB C Driver2.1.0 – 2.1.2—No fix listedCNA
  • MongoDB C Driver VendorMongoDB Affected 2.1.0 – 2.1.2 Fixed in — No fix listed CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:mongodb:c_driver:*:*:*:*:*:mongodb:*:*2.1.0 to before 2.1.2VulnerableMongoDB
  • cpe:2.3:a:mongodb:c_driver:*:*:*:*:*:mongodb:*:* Versions 2.1.0 to before 2.1.2 Vulnerable ·MongoDB

Remediation

No fixed version listed by the sources yet.

Vendor assessments

Red Hat

Red Hat's page for this CVE →

Not affected: 1 product
  • Red Hat

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-6691
  2. 2026-10-03 Alias added: GHSA-587q-94wg-2pfp

References

Patch 1

  • TI-2026-62966 Heap overflow via oversized decrypted TLS record sequence in Windows Secure Channel stream CVSS 4.0CRITICAL 9.2
  • TI-2026-62968 Integer Underflow → Heap Out-of-Bounds Read in `bson_new_from_buffer() CVSS 4.0MEDIUM 6.9
  • TI-2024-07001 Accessing Untrusted Directory May Allow Local Privilege Escalation CVSS 3.1HIGH 7.8
  • TI-2026-58387 Heap corruption via OCSP request double free from crafted multi-URL certificate in TLS client CVSS 4.0HIGH 8.2
  • TI-2023-00414 MongoDB client C Driver may infinitely loop when validating certain BSON input data CVSS 3.1HIGH 7.5
  • TI-2026-58386 Silent field truncation via unchecked int cast of huge JSON string values in JSON-to-BSON parser CVSS 4.0MEDIUM 6.3
See all 20 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences