Bug 2548201 (CVE-2026-106434)

Summary: CVE-2026-106434 libmongocrypt: libmongocrypt: Processing of raw data as plaintext via missing decryption error
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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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 MongoDB libmongocrypt. When processing an unrecognized encrypted payload during explicit decryption, the library returns the data unchanged instead of generating a decryption error. An attacker capable of modifying stored encrypted fields, such as a compromised database server or network intermediary, can supply arbitrary data. As a result, the affected application mistakenly treats the raw data as valid decrypted plaintext, leading to data integrity issues.
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Bug Depends On: 2548580, 2548581    
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Description OSIDB Bzimport 2026-10-08 19:11:33 UTC 
The explicit decryption component of MongoDB libmongocrypt can return an unrecognized encrypted payload unchanged instead of returning a decryption error. An actor who can modify stored encrypted fields, such as a database writer, server, or network intermediary, can cause an affected application to process the supplied bytes as decrypted plaintext.