Heap buffer overflow via wrapped size check during SASL username canonicalization in MongoDB C Driver (CVE-2026-88035) | HOL Guard CVE

Unknown severity · Source severity not reportedCVE-2026-88035

Heap buffer overflow via wrapped size check during SASL username canonicalization in MongoDB C Driver

Answer in brief

CVE-2026-88035 records a Unknown severity vulnerability in Heap buffer overflow via wrapped size check during SASL username canonicalization 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 Sep 10, 2026Updated Sep 10, 2026Source checked Sep 10, 2026First seen by HOL Sep 10, 2026Material review Sep 10, 2026

Upstream Advisory

Key facts

Risk: Unknown severitySource severity not reported
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Available

Why this deserves its current priority

A CVSS score is not reported in the current record. 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	>=2.2.0 <2.5.3	2.5.3

Recommended response

Check inventory. Check lockfiles and deployed manifests for MongoDB/C Driver.
Review the reported fix. Update MongoDB/C Driver to 2.5.3 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Sep 10, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 10, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Sep 10, 2026

Sources and claim methodology

Source referencejira.mongodb.org

Upstream source description

A size check in the client-side authentication path of the MongoDB C Driver can wrap around, so an unusually large user-name value is accepted and copied past the end of a small buffer. A party able to set the driver's connection settings may cause the application that embeds the driver to terminate unexpectedly. Reaching this code requires a build in which the optional external SASL authentication backend is present and a connection configured to use it.

Quoted source text, attributed separately from HOL analysis.