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Fencer Vulns
medium 4.3

CVE-2026-6231 json

bson_validate may skip validation when processing certain inputs

published 2026-04-13 6 mo ago modified 2026-10-26 13 d ago also EUVD-2026-22023 , JLSEC-2026-773

cvss
4.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 8%
public exploits
0
none known

Summary

The bson_validate function may return early on specific inputs and incorrectly report success. This behavior could result in skipping validation for BSON data, allowing malformed or invalid UTF-8 sequences to bypass validation and be processed incorrectly. The issue may affect applications that rely on these functions to validate untrusted BSON data before further processing. This issue affects MongoDB C Driver versions prior to 1.30.5, MongoDB C Driver version 2.0.0 and MongoDB C Driver version 2.0.1

Patch / fix

  • julia MongoC_jll 1.30.8+0
  • MongoDB Inc. C Driver 1.30.5, 2.0.2
  • mongo-c-driver Debian 12 1.23.1-1+deb12u3
  • mongo-c-driver Debian 13 1.30.4-1+deb13u2
  • mongo-c-driver Debian 14 2.1.0-1

debian advisories DEBIAN-CVE-2026-6231

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-6231 updated cvss 4.3

mongo-c-driver: bson_validate may skip validation when processing certain inputs

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
6 mo ago

Exploit prediction

0.18% chance of exploitation in the next 30 days, higher than 8% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 4.0 5.3 CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
CNA 3.1 4.3 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
CNA 4.0 5.3 CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/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:X
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
OSV 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Affected packages

ecosystem package affected fixed in
julia MongoC_jll
<1.30.8+0
1.30.8+0

Affected products

  • MongoDB Inc. C Driver

Classification

Weakness
  • CWE-20 Improper Input Validation

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.