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Fencer Vulns
medium 5.9

CVE-2026-114650 json

Plaintext exposure of encrypted fields via ANSI code-page corruption of database name

published 2026-10-22 17 d ago modified 2026-11-02 6 d ago also EUVD-2026-108319

cvss
5.9
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.1%
EPSS 0.1% chance of exploitation in 30 days, percentile 1%
public exploits
0
none known

Summary

A flaw in the client-side encryption support of the MongoDB .NET/C# driver can cause data designated for client-side field-level encryption to be written without encryption. Under certain platform text-encoding configurations, an internal name conversion loses information, so the encryption layer fails to associate the operation with its configured encryption rules and the operation proceeds without an error being raised. An application user with the ability to write data through an affected application can therefore have sensitive fields persisted in plaintext, defeating the confidentiality guarantee that client-side encryption is intended to provide. No integrity or availability impact was observed.

Patch / fix

  • MongoDB C# Driver 3.13.0

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
6 d ago

Exploit prediction

0.11% chance of exploitation in the next 30 days, higher than 1% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/mongodb/mongo-csharp-driver/security/advisories/GHSA-jvpx-6w8x-h6rg referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 4.0 6.9 CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N
CNA 3.1 5.9 CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:C/C:H/I:N/A:N
CNA 4.0 6.9 CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected products

  • MongoDB C# Driver
  • MongoDB MongoDB.Libmongocrypt NuGet package

Classification

Weakness
  • CWE-838 Inappropriate Encoding for Output Context

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.