CVE-2026-106431: medium-severity vulnerability in MongoDB C Driver
One-byte heap buffer overflow in BSON bulk document writer in MongoDB C Driver
Published
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13Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 5.9epss 0.1%
An off-by-one error in the BSON bulk document writer in the MongoDB C Driver can write one zero byte immediately past a heap allocation when a document ends at a specific buffer boundary. An actor who can influence the size of documents serialized by an embedding application can corrupt adjacent process memory or terminate the process. Reaching this issue requires the application to use the BSON bulk-writer API and produce a precise cumulative document size.
CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N
Affected products
MongoDB · C DriverRelated CVEs — MongoDB C Driver
In the same product, most dangerous first.
CVE-2026-96746HIGHHeap buffer overflow via mid-scan command list growth in client topology monitoringEPSS 0.4%CVE-2026-120678HIGHMongoDB C Driver leaks the decompressed reply buffer when an OP_COMPRESSED reply fails to parse (denial of service)EPSS 0.4%CVE-2026-120955HIGHMongoDB C Driver Modern GridFS mongoc_gridfs_bucket_download_to_stream() Aborts Application on Malformed GridFS MetadataEPSS 0.4%CVE-2026-120684MEDIUMMongoDB C Driver GridFS gap lets a shared writer recover a protected client's passwordEPSS 0.3%CVE-2026-84963MEDIUMSilent field truncation via unchecked int cast of huge JSON string values in JSON-to-BSON parserEPSS 0.3%CVE-2026-84969MEDIUMHeap overflow via truncated base64 encoding of binary fields in length-limited JSON outputEPSS 0.3%