CVE-2026-106433 MongoDB libmongocrypt - Out of Bounds Read/Write

MongoDB libmongocrypt contains an out-of-bounds memory access caused by improper state management when cleaning up key documents with duplicate masterKey fields, letting authenticated actors cause application termination or memory corruption, exploit requires ability to modify key vault documents.

CVSS base score 8.8 /10
High
CISA KEV
Not listed
Public exploit
None known
Authentication
Required
EPSS
0.27% chance of exploitation in 30 days
View the NVD record ↗

Details

Type
Out of Bounds Read/Write
Impact
Denial Of Service
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Published
8 October 2026
Updated
15 October 2026
Weakness
CWE-843

Vendor fix

Update to the latest version of libmongocrypt containing the fix.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

References

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