High severity · published Oct 8, 2026
CVE-2026-106433
Heap corruption via duplicate masterKey fields in MongoDB libmongocrypt
8.8
CVSS
0.3%
EPSS
No
On KEV
Description
Improper state management in MongoDB libmongocrypt can cause provider-specific data to be treated as an incompatible type when cleaning up a key document containing duplicate masterKey fields. An authenticated actor who can modify key vault documents, or a server that returns such a key document, can cause invalid memory access and invalid frees in the client process. This can terminate the application or corrupt process memory.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 19% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
MO
MongoDB · MongoDB
1.1.0 before 1.20.5 · source: vendor
LI
Libmongocrypt · Mongodb
1.5.0 before 1.20.5 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-106433
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-106433
jira.mongodb.org
https://jira.mongodb.org/browse/MONGOCRYPT-964
More from MongoDB
9.9
CVE-2019-10758
MongoDB mongo-express Remote Code Execution Vulnerability
7.5
CVE-2025-14847
Zlib compressed protocol header length confusion may allow memory read
9.8
CVE-2026-19001
MongoDB BI Connector ODBC driver may write outside an allocated buffer when handling oversized catalog object names
9.8
CVE-2025-3085
A MongoDB server under specific conditions running on Linux with TLS and CRL revocation status checking enabled, fails to check the revocation status of the intermediate…
9.8
CVE-2024-8654
MongoDB Server may access non-initialized region of memory leading to unexpected behaviour