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Medium 6.5Published Oct 22, 2026

CVE-2026-114654BSON output corruption via out-of-range binary subtype bypassing UUID and OldBinary guards

Updated under an hour ago ()

Does this affect you?

It affects MongoDB C# Driver. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

A numeric-type conversion flaw in the BSON handling library of the MongoDB C# Driver allows an out-of-range binary subtype value supplied through untrusted textual input to bypass the library's binary-element integrity checks. When such a value is later encoded, it is narrowed to a smaller wire representation, producing binary elements that misdeclare their type or length. An unauthenticated party able to supply text parsed by an affected application can cause it to emit and persist malformed binary data, which subsequent readers either reject with an error or silently interpret as shorter than the data that was validated.

CVSS
6.5 MEDIUM (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L
Weakness (CWE)
CWE-681
Known exploited
Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days)
Not loaded for this CVE
Assigned by
mongodb
NVD analysis
Awaiting Analysis
Record last updated
Oct 22, 2026
First seen by InfoSec Signals
Oct 22, 2026

Affected products

Affected products
MongoDB C# Driver
mongodb:c_driver (from the name)
from 2.0.0 before 3.13.0
CNA record

References

References

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.

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