CVE-2026-6691

highpriority · track · 0EPSS 0.001 · 2 %ileDEEURUUS

grimoire priorityP2 · Scheduled

Exploitable?

—

no known exploitation

Likely / severe?

0.13% (2nd) EPSS

CVSS 7.8 · high

Is it mine?

15 products

Check your exposure

Who says so?

5 sources

cnnvd · enisa_euvd · fstec_bdu · cert_bund

EPSS · scored 2026-10-28

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

Technical severity, 0–10. One row per scoring source.

8.6

010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 6.1–8.6

v3.17.8highAV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:Hsecondary · FSTEC (BDU) RU

v3.17.8highCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:Hsecondary · cna@mongodb.comexploitability 1.8 · impact 5.9

v4.08.6highCVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:Nsecondary · ENISA EU

v4.08.6highCVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:Xsecondary · cna@mongodb.com

v4.06.1mediumCVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:Xsecondary · CVSS-BT (t0sche)

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Exploitation: none · Automatable: no · Technical Impact: totalcoordinatorcisa_ssvcUS

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-787USprimaryCWE-120USCWE-120USCWE-787US

affected products (15)

Products and version ranges known to be affected.

Open Source MongoDB C Driver <2.1.3all versionscert_bundDE
Open Source MongoDB C Driver <2.2.0all versionscert_bundDE
Open Source MongoDB≤ C Driver <2.2.0cert_bundDE
Open Source MongoDB≤ C Driver <2.1.3cert_bundDE
MongoDB Inc. MongoDB C Driver≤ 2.1.0 ≤2.1.2enisa_euvdEU
MongoDB Inc. MongoDB C Driver≤ 2.2.0fstec_bduRU
ООО «Ред Софт» РЕД ОС≤ 8.0fstec_bduRU
ООО «Ред Софт» РЕД ОС≤ 7.3fstec_bduRU
ООО «РусБИТех-Астра» Astra Linux Special Edition≤ 1.7fstec_bduRU
ООО «РусБИТех-Астра» Astra Linux Special Edition≤ 4.7fstec_bduRU
Сообщество свободного программного обеспечения Debian GNU/Linux≤ 12fstec_bduRU
Сообщество свободного программного обеспечения Debian GNU/Linux≤ 10fstec_bduRU
Сообщество свободного программного обеспечения Debian GNU/Linux≤ 11fstec_bduRU
Сообщество свободного программного обеспечения Debian GNU/Linux≤ 13fstec_bduRU
mongodb c driver2.1.0 → 2.1.2nvdUScpe:2.3:a:mongodb:c_driver:*:*:*:*:*:*:*:*

advisories (1)

Vendor and ecosystem advisories describing this.

WID-SEC-W-2026-1386MongoDB: Schwachstelle ermöglicht CodeausführungDeutsch2026-05-06csaf · cert_bundDE
Ein lokaler Angreifer kann eine Schwachstelle in MongoDB ausnutzen, um beliebigen Programmcode auszuführen.

also known as (4)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd fstec_bdu cert_bund nvd NVD CVE.org MITRE

published 2026-05-06modified 2026-10-26

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Related entries.

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+16132 more

references (4)

External citations — patches, advisories, analysis.

https://jira.mongodb.org/browse/CDRIVER-6134Patchcnnvd
https://nvd.nist.gov/vuln/detail/CVE-2026-6691 cnnvd
https://jira.mongodb.org/browse/CDRIVER-6134 enisa_euvd
https://jira.mongodb.org/browse/CDRIVER-6134PatchVendor AdvisoryIssue Trackingnvd

scry

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