LiveActive security incident?Get immediate response
CVE Record

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

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.

CriticalCVSS 9.8Not KEV-listedUpdated
Discuss exposureBack to CVEs
Glexia's TakeAutomated analysiscritical

Security readout for executives and security teams

Plain-English summary

A remote, unauthenticated attacker who can reach a vulnerable MOOSDB service may corrupt heap memory before login. Successful exploitation could crash the service or potentially compromise its confidentiality and integrity. The supplied evidence rates the issue critical, but does not establish active exploitation.

Executive priority

Address immediately where vulnerable MOOSDB services are internet-facing or accessible from untrusted segments. Require rapid inventory and containment, then deploy a vendor-supported correction when available. Internally isolated systems remain important but can follow exposed systems after reachability is verified.

Technical view

MOOS core-moos through 10.4.0 reportedly mishandles negative packet lengths in MOOSCommPkt::InflateTo(). Signed-length validation and conversion during recv() can permit attacker-controlled data to overflow a four-byte heap allocation during the pre-authentication HandShake phase. The reported weakness is CWE-787 with CVSS 3.1 score 9.8.

Likely exposure

Exposure is highest where MOOSDB from core-moos through 10.4.0 is reachable from untrusted networks. Authentication does not prevent the vulnerable handshake path. The supplied affected-version metadata is internally inconsistent, so organizations should verify deployed versions and applicability against vendor guidance.

Exploitation context

The vulnerability is network-accessible, requires no privileges or user interaction, and has low reported attack complexity. The bundle states arbitrary data can be written, implying possible code execution, corruption, or denial of service. It is not listed as KEV, and the supplied sources provide no evidence of active exploitation.

Researcher notes

The key sink is reported in MOOSCommPkt.cpp during packet inflation and handshake reception. Negative signed lengths may bypass checks before conversion to a receive size, producing a heap overwrite. A proposed fix exists, but the bundle identifies it as unmerged. Version applicability should be independently reconciled because structured affected data conflicts with the narrative range.

Mitigation direction

  • Identify MOOSDB instances and restrict their listeners to trusted networks while remediation is evaluated.
  • Block unnecessary external access using network controls and host firewalls.
  • Check vendor guidance for an official supported fix or release.
  • Treat the referenced unmerged pull request and commit as proposed, not a confirmed production update.
  • Prioritize isolation or shutdown of unnecessary vulnerable services when adequate access controls are unavailable.

Validation and detection

  • Inventory core-moos and MOOSDB versions, including embedded or manually compiled deployments.
  • Confirm whether each MOOSDB listener is reachable from untrusted networks.
  • Verify remediation status against the upstream pull request, repository releases, and vendor guidance.
  • Review service crashes and memory-corruption indicators around unauthenticated handshake traffic.
  • After remediation, confirm network restrictions remain effective and deployed binaries contain the approved fix.
Prepared
Confidence
medium
Sources
6

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cwe · low confidence lookup

CWE-787: Exact CWE lookup

Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

Open ATT&CK lookup
cve · low confidence lookup

CVE-2026-85440 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

Open ATT&CK lookup
Vulnerability profileCVE Program record
Severity
Critical
CVSS
9.8 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

2CVSS vectors
3Timeline events
1ADP providers
6Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: yesTechnical Impact: total

CVSS vector scores

2 official scores

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
9.8CVSS 3.1CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H3.95.9VulnCheck
9.3CVSS 4.0CriticalCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N——VulnCheck

Vulnerability scoring details

Base CVSS 4.0 score

9.3Critical
CVSS 4.0 vector shape for CVE-2026-85440Attack VectorAttack ComplexityAttack RequirementsPrivileges RequiredUser InteractionVS ConfidentialityVS IntegrityVS AvailabilitySS ConfidentialitySS IntegritySS Availability

Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Attack Requirements
NonePresent
Privileges Required
NoneLowHigh
User Interaction
NonePassiveActive
VS Confidentiality
HighLowNone
VS Integrity
HighLowNone
VS Availability
HighLowNone
SS Confidentiality
HighLowNone
SS Integrity
HighLowNone
SS Availability
HighLowNone

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
other:ssvc

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
themooscore-moos0unaffected
Weakness

CWE details

CWE-787

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.

CWE-787 · source CWE mapping

Out-of-bounds Write

Out-of-bounds Write represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

Open CWE intelligenceSame-CWE CVEs