Bug 2548209 (CVE-2026-106429)

Summary: CVE-2026-106429 libmongocrypt: libmongocrypt: Denial of Service via integer underflow in KMS endpoint parsing
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
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Priority: medium    
Version: unspecifiedKeywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in libmongocrypt. An integer underflow in the Key Management Service (KMS) endpoint-parsing logic can cause a memory allocation failure when processing a malformed endpoint. An authenticated user can trigger this flaw by modifying a key document in the key vault collection or by supplying an endpoint with an unexpected colon character during key creation. Exploitation causes the application process to terminate unexpectedly, resulting in a Denial of Service (DoS).
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Bug Depends On: 2548571, 2548575    
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Description OSIDB Bzimport 2026-10-08 19:12:34 UTC 
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.