5.9

CVE-2026-106431: mongodb c_driver Out-of-bounds Write

CVSS: 5.9v4.0MediumAwaiting analysis
AliasesDEBIAN-CVE-2026-106431UBUNTU-CVE-2026-106431
Published 08-10-2026Last modified 08-10-2026
Open JSON

Vulnerability summary

CVE-2026-106431 is a medium (CVSS 5.9) Out-of-bounds Write vulnerability in mongodb c_driver. EPSS estimates a 0.10% chance of exploitation in the next 30 days, higher than 0.6% of scored vulnerabilities.

Overall risk
24/100
0100
Low · default modelHow is this calculated?
CVSS score
5.9/10
010
Medium · v4.0 (CVE.org)
EPSS score
0.10%
0%100%
Low · Change unavailable
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Timeline

  1. 08-10-2026
    PublishedVulnerability first disclosed.
  2. 08-10-2026
    Last modifiedVulnerability information updated.

Description

An off-by-one error in the BSON bulk document writer in the MongoDB C Driver can write one zero byte immediately past a heap allocation when a document ends at a specific buffer boundary. An actor who can influence the size of documents serialized by an embedding application can corrupt adjacent process memory or terminate the process. Reaching this issue requires the application to use the BSON bulk-writer API and produce a precise cumulative document size.

CVSS metrics

7 scores · 4 sources · 2 versions

EPSS trend

Probability

0.10%

Chance of exploitation in the next 30 days

Percentile

1%

Versus all other CVEs

30-day change

Change unavailable

Change unavailable

09-10-202620-10-2026
EPSS score
0.10%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Debian1 product
  • mongo-c-driverAll versions (No fix recorded) | < 2.5.6-1
Mongodb1 product
  • c_driver≥ 0.5.0, < 1.30.13 | ≥ 2.0.0, < 2.5.6
Ubuntu1 product
  • mongo-c-driverAll versions (No fix recorded)

3 vendors · 3 products

References

4 links