What’s Vulnerable › Vulnerabilities

CVE-2026-114655: KMS request injection via unsanitized key vault and provider values in libmongocrypt

• Severity: medium (CVSS 5.9 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-22 · updated 2026-10-30
• Weakness: CWE-74

Description

libmongocrypt builds requests to external key management services (AWS, Azure and GCP) by inserting values from key vault documents, KMS provider configuration and KMS responses into request lines, headers and signed request bodies without validating or encoding them for each context. A user with write access to the key vault collection can alter the structure of these requests, including adding members to request bodies and token claims that the library then signs with the application's credentials. This may result in key management operations being performed with parameters the application did not intend.

Affected products

• MongoDB libmongocrypt: from 1.0.0 before 1.21.1 — fixed in 1.21.1

How to fix

Upgrade to a fixed version: MongoDB libmongocrypt 1.21.1. Check the vendor advisory for mitigations.

References

• https://github.com/mongodb/libmongocrypt/releases/tag/1.21.1
• https://github.com/mongodb/libmongocrypt/security/advisories/GHSA-7mvq-mg47-m88j
• https://jira.mongodb.org/browse/MONGOCRYPT-963

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