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PatchSiren cyber security CVE debrief

CVE-2026-38999 Monkey CVE debrief

CVE-2026-38999 is a high-severity vulnerability in the Monkey server, which allows attackers to cause a Denial of Service (DoS) via a crafted HTTP request. The vulnerability is caused by a null pointer dereference in the mk_sched_event_close function. Defenders should assess exposure, prioritize remediation, and verify vulnerability status. This vulnerability affects systems using the Monkey server, particularly those with unpatched versions. The vulnerability's severity and potential impact necessitate prompt attention from defenders.

Vendor
Monkey
Product
Monkey server
CVSS
HIGH 7.5
CISA KEV
Not listed in stored evidence
Original CVE published
2026-09-16
Original CVE updated
2026-09-22
Advisory published
2026-09-16
Advisory updated
2026-09-22

Who should care

Defenders responsible for systems using the affected Monkey server version should assess exposure and prioritize remediation. This includes operators, platform administrators, vulnerability management teams, and security teams. They should verify vulnerability status, apply patches or updates if available, and monitor for potential DoS attacks.

Why it matters

CVE-2026-38999 is a high-severity vulnerability in the Monkey server that allows attackers to cause a Denial of Service (DoS). Defenders should assess exposure, prioritize remediation, and verify vulnerability status.

  • Denial of Service (DoS) via crafted HTTP requests
  • Potential disruption of service or system availability
  • Need for vulnerability verification and patch application

Technical summary

The vulnerability is caused by a null pointer dereference in the mk_sched_event_close function of the Monkey server. This allows attackers to cause a Denial of Service (DoS) via a crafted HTTP request. The affected function is located in the mk_server/mk_scheduler.c file. The vulnerability's technical details indicate a high level of severity, emphasizing the need for prompt remediation.

Defensive priority

Defenders should assess exposure and prioritize remediation for systems using the affected Monkey server version.

Recommended defensive actions

  • Assess exposure and prioritize remediation for systems using the affected Monkey server version
  • Verify vulnerability status and apply patches or updates if available
  • Monitor for potential DoS attacks and implement compensating controls if necessary

Evidence notes

The vulnerability is described in the CVE record and NVD vulnerability detail page. Additional information is available in source references from GitHub.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-38999 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-38999

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-38999 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-38999

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.