A high-severity safety flaw has been disclosed in MongoDB that might enable unauthenticated customers to learn uninitialized heap reminiscence.
The vulnerability, tracked as CVE-2025-14847 (CVSS rating: 8.7), has been described as a case of improper dealing with of size parameter inconsistency, which arises when a program fails to appropriately deal with eventualities the place a size discipline is inconsistent with the precise size of the related knowledge.
“Mismatched size fields in Zlib compressed protocol headers could enable a learn of uninitialized heap reminiscence by an unauthenticated consumer,” in keeping with a description of the flaw in CVE.org.
The flaw impacts the next variations of the database –
- MongoDB 8.2.0 via 8.2.3
- MongoDB 8.0.0 via 8.0.16
- MongoDB 7.0.0 via 7.0.26
- MongoDB 6.0.0 via 6.0.26
- MongoDB 5.0.0 via 5.0.31
- MongoDB 4.4.0 via 4.4.29
- All MongoDB Server v4.2 variations
- All MongoDB Server v4.0 variations
- All MongoDB Server v3.6 variations
The problem has been addressed in MongoDB variations 8.2.3, 8.0.17, 7.0.28, 6.0.27, 5.0.32, and 4.4.30.
“An client-side exploit of the Server’s zlib implementation can return uninitialized heap reminiscence with out authenticating to the server,” MongoDB stated. “We strongly suggest upgrading to a set model as quickly as potential.”
If instant replace shouldn’t be an choice, it is really helpful to disable zlib compression on the MongoDB Server by beginning mongod or mongos with a networkMessageCompressors or a web.compression.compressors choice that explicitly omits zlib. The opposite compressor choices supported by MongoDB are snappy and zstd.
“CVE-2025-14847 permits a distant, unauthenticated attacker to set off a situation by which the MongoDB server could return uninitialized reminiscence from its heap,” OP Innovate stated. “This might consequence within the disclosure of delicate in-memory knowledge, together with inside state info, pointers, or different knowledge which will help an attacker in additional exploitation.”

