# CVE-2026-106429: libmongocrypt: An integer underflow in the KMS endpoint-parsing logic of MongoDB libmongocrypt can cause an allocation failure that...

CVE-2026-106429 is fixed in libmongocrypt on 1 platform by DEBIAN-CVE-2026-106429 (version 1.20.5-1), released October 16, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-106429
- Priority: Routine
- CVSS: n/a
- EPSS: 0.0029
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Oct 8, 2026

## Description

An integer underflow in the KMS endpoint-parsing logic of MongoDB libmongocrypt can cause an allocation failure that terminates the application process. This can occur when an authenticated user modifies a key document in the key vault collection, or when an application accepts a KMS endpoint containing a colon after its path or query during key creation. The issue does not access memory outside its allocated bounds.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | libmongocrypt Debian 14 | 1.20.5-1 | [DEBIAN-CVE-2026-106429](https://patchblox.com/security/data/fix/linux/debian-cve-2026-106429.md) | Oct 16, 2026 |

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Data as of 2026-11-09T19:38:12Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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