CVE-2026-81528 NoSQL injection via array replacement bypassing update shape validation in driver write path
Attackers can inject NoSQL commands via untrusted input in document replacement operations, leading to unauthorized database access or modification.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-81528?
CVE-2026-81528 is a medium-severity SQL injection vulnerability in MongoDB C# Driver, published on 27 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
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.
Weakness: CWE-943
Which versions are affected by CVE-2026-81528?
It affects 1 product.
Products include Mongodb C\# Driver.
How do I fix CVE-2026-81528?
No fix has been published for CVE-2026-81528 yet. Limit exposure of the affected software until one is available.
Use parameterised queries everywhere and never build SQL by joining strings. Upgrade affected software first; a web application firewall only buys time. More about SQL injection.
Is CVE-2026-81528 being exploited?
There is no known exploitation of CVE-2026-81528 in the wild and no public exploit code.
Other vulnerabilities in MongoDB C# Driver
- CVE-2026-88026 Regular expression injection via unescaped characters in LINQ query translation in MongoDB C# Driver
- CVE-2026-81529 Connection-option injection via unescaped settings in the canonical MongoDB URL builder
- CVE-2026-81527 NoSQL injection via unquoted constant GroupBy keys in LINQ pipeline translation
- CVE-2026-81530 KMS master key exposure via unredacted credential serialization in driver settings string
- CVE-2022-48282 Deserializing compromised object with MongoDB .NET/C# Driver may cause remote code execution
Sources
Also known as GHSA-3jfm-hm2c-wrqh.