Medium · CVSS 5.1CVE-2026-106438

Silent Decimal128 value corruption via incorrect exactness check in MongoDB C DriverCVE-2026-106438

Answer in brief

CVE-2026-106438 records a Medium severity (CVSS 5.1) vulnerability in Silent Decimal128 value corruption via incorrect exactness check in MongoDB C Driver. The current sources do not mark it as known exploited. The current feed maps MongoDB/C Driver (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Oct 8, 2026Updated Oct 8, 2026Source checked Oct 8, 2026First seen by HOL Oct 8, 2026Material review Oct 8, 2026

Upstream Advisory

Key facts

Risk: Medium · CVSS 5.1
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Available

Why this deserves its current priority

CVSS is 5.1. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps MongoDB/C Driver (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
MongoDB/C Drivergeneric	>=1.4.0 <1.30.13 \|\| >=2.0.0 <2.5.6	1.30.13, 2.5.6

Recommended response

Check inventory. Check lockfiles and deployed manifests for MongoDB/C Driver.
Review the reported fix. Update MongoDB/C Driver to 1.30.13 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Oct 8, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Oct 8, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Oct 8, 2026

Sources and claim methodology

Source referencejira.mongodb.org

Upstream source description

An incorrect calculation in Decimal128 string parsing in the MongoDB C Driver can accept certain over-precision inputs containing leading zeros instead of rejecting them. This produces a value different from the supplied text. An actor who can provide a decimal string to an embedding application, including through Extended JSON parsing, can cause the application to store or use an incorrect numeric value.

Quoted source text, attributed separately from HOL analysis.