NoSQL injection via array replacement bypassing update shape validation in driver write path
Key facts
- Attack vector
- Network
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Attack requirements
- None
- Impact type
- —
- Confidentiality · integrity · availability
- Low · Low · None
- Fix status
- Fixed
Attack profile from CVSS 4.0 · CNA. Fix status from CNA.
Summary
A MongoDB C# driver document-replacement code path omits the element-name/shape validation that the equivalent write paths apply, so a value supplied as a replacement is forwarded to the server without neutralization of query-language special elements. An application that passes untrusted, loosely-typed input as a replacement value therefore allows that input to be interpreted by the database as update logic rather than as data, executing under the application's own database credentials. Applications using strongly-typed document mappings are not affected.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
Remediation
- Fix · CNA C# Driver (MongoDB) Fixed in 3.11.1
Fixed in the same release
Records fixed by the same vendor advisory or release, as the CNA lists them.
- Release ·
MongoDB C# Driver 3.11.1
4 records Highest priority Priority LOW 4 LOW
Other records, highest priority first
- TI-2026-56248 NoSQL injection via unquoted constant GroupBy keys in LINQ pipeline translationPriority LOW 36
- TI-2026-56250 Connection-option injection via unescaped settings in the canonical MongoDB URL builderPriority LOW 31
- TI-2026-56251 KMS master key exposure via unredacted credential serialization in driver settings stringPriority LOW 29
Timeline
- 2026-10-02 Threatist record created from CVE-2026-81528
- 2026-10-03 Alias added: GHSA-3jfm-hm2c-wrqh
References
More MongoDB C# Driver vulnerabilities
- TI-2026-56248 NoSQL injection via unquoted constant GroupBy keys in LINQ pipeline translation CVSS 4.0MEDIUM 6.9
- TI-2022-23899 Deserializing compromised object with MongoDB .NET/C# Driver may cause remote code execution CVSS 3.1HIGH 7.2
- TI-2026-60051 Regular expression injection via unescaped characters in LINQ query translation in MongoDB C# Driver CVSS 4.0HIGH 7.1
- TI-2026-56250 Connection-option injection via unescaped settings in the canonical MongoDB URL builder CVSS 4.0HIGH 7.1
- TI-2026-56251 KMS master key exposure via unredacted credential serialization in driver settings string CVSS 4.0MEDIUM 6.8
- TI-2026-60050 GridFS data disclosure and deletion via query-operator injection in file IDs in the MongoDB C# Driver CVSS 4.0MEDIUM 6.1
Sources
- CVE-2026-81528 · CVE Program
- CVE-2026-81528 · NVD
- FIRST EPSS
- GHSA-3jfm-hm2c-wrqh · GitHub Advisory Database · CC BY 4.0
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