High severity · published Aug 28, 2026
CVE-2026-81517
MongoDB Connector for BI Improper Error Handling of Log Write Failures May Cause Loss of SQL Service
7.5
CVSS
0.5%
EPSS
No
On KEV
Description
An unauthenticated party able to reach the port of a MongoDB Connector for BI (mongosqld) instance may generate enough routine connection log activity to exhaust the storage backing the configured log path. When a log write or log rotation operation subsequently fails, the resulting error is not handled and the shared mongosqld process ends, ending service for all connected SQL clients. The process continues to end on startup until an operator restores available storage, and the diagnostic message explaining the condition is not recorded.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.5% · higher than 40% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
MO
MongoDB · MongoDB
before 2.14.31 · source: vendor
BC
BI Connector · Mongodb
before 2.14.31 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-81517
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-81517
Vendor Advisory
https://www.mongodb.com/docs/bi-connector/current/release-notes/
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