Critical 9.8Published Sep 3, 2026

CVE-2026-85440MOOS core-moos through 10.4.0 MOOSDB Pre-Authentication Heap Overflow via Negative Packet Length

Updated under an hour ago (Oct 30, 2026, 12:00 AM ET)

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It affects themoos core-moos and 1 other product. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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MOOS core-moos through 10.4.0 contains a pre-authentication heap overflow vulnerability in MOOSCommPkt packet handling that allows remote attackers to write arbitrary data by declaring a negative packet length. Attackers can exploit the signed integer check in InflateTo() and negative size conversion in recv() to overflow a four-byte heap buffer during the HandShake phase before authentication.

CVSS: 9.8 CRITICAL (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness (CWE): CWE-787
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: VulnCheck
NVD analysis: Analyzed
Record last updated: Sep 4, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

themoos core-moos themoos:core_moos (from the name)	through 10.4.0	CNA record
themoos core-moos themoos:core-moos	before 10.4.0	NVD

References

References

https://github.com/themoos/core-moos/pull/82	issue-tracking, patch
https://github.com/themoos/core-moos/commit/96c49c5cdda6e07ee734a5324e8d25ba5a7f2d7a	patch, issue-tracking
https://github.com/themoos/core-moos	product
https://github.com/themoos/core-moos/blob/ec9c77c68fcbdef8f5e4c60fe243acd223433f0c/Core/libMOOS/Comms/MOOSCommPkt.cpp#L67	technical-description, issue-tracking, patch
https://www.vulncheck.com/advisories/moos-core-moos-through-10.4.0-moosdb-pre-authentication-heap-overflow-via-negative-packet-length	third-party-advisory

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.