CVE-2026-85440

CRITICALPre-NVD 9.89.8—
EchelonGraph scoreHIGH confidence

Score 9.8 from GitHub Security Advisory (severity: CRITICAL) published 2026-09-04. a secondary CVSS source baseline 9.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 3 sources updated this week
9.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 9.8Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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 v3
9.8
EG Score
9.8(high)
EG Risk
59(Track)
EG Risk 59/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity98% × 45%
Exploitation1% × 40%
Automatability100% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
1%
EPSS %ILE
45%
KEV
Not listed

Published

September 3, 2026

Last Modified

September 8, 2026

Advisory Details (5)

Auto-updated Sep 16, 2026
Upstream fix merged — awaiting tagged release. Sources: github_commit, github_pr.
generic

MOOS core-moos through 10.4.0 MOOSDB Pre-Authentication Heap Overflow via Negative Packet Length | Advisories | VulnCheck

https://www.vulncheck.com/advisories/moos-core-moos-through-10.4.0-moosdb-pre-authentication-heap-overflow-via-negative-packet-length
github_pr

Reject negative packet lengths in CMOOSCommPkt

Upstream fix in progress (PR #82 · themoos/core-moos, state=open)

https://github.com/themoos/core-moos/pull/82
github_commit

commit 96c49c5cdda6 (themoos/core-moos)

Fix landed in themoos/core-moos commit 96c49c5cdda6 — awaiting tagged release

https://github.com/themoos/core-moos/commit/96c49c5cdda6e07ee734a5324e8d25ba5a7f2d7a
generic

core-moos/Core/libMOOS/Comms/MOOSCommPkt.cpp at ec9c77c68fcbdef8f5e4c60fe243acd223433f0c · themoos/core-moos · GitHub

https://github.com/themoos/core-moos/blob/ec9c77c68fcbdef8f5e4c60fe243acd223433f0c/Core/libMOOS/Comms/MOOSCommPkt.cpp#L67
generic

GitHub - themoos/core-moos: A very light weight, easy to use middleware. You will need core-moos above all other components · GitHub

https://github.com/themoos/core-moos

Vendor Advisories for CVE-2026-85440(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 52× in last 7d / 127× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 127 total refreshes for this CVE.

  1. 2026-09-20 12:31 UTCGHSA enrichment
  2. 2026-09-20 08:09 UTCGHSA enrichment
  3. 2026-09-20 03:07 UTCGHSA enrichment
  4. 2026-09-19 22:54 UTCGHSA enrichment
  5. 2026-09-19 18:43 UTCEG score recompute
  6. 2026-09-19 18:43 UTCGHSA enrichment
  7. 2026-09-19 14:32 UTCGHSA enrichment
  8. 2026-09-19 10:18 UTCGHSA enrichment
  9. 2026-09-19 06:06 UTCGHSA enrichment
  10. 2026-09-19 01:54 UTCGHSA enrichment
  11. 2026-09-18 21:42 UTCEG score recompute
  12. 2026-09-18 21:42 UTCGHSA enrichment
  13. 2026-09-18 19:28 UTCEPSS rescore
  14. 2026-09-18 17:31 UTCGHSA enrichment
  15. 2026-09-18 13:18 UTCGHSA enrichment
  16. 2026-09-18 09:07 UTCGHSA enrichment
  17. 2026-09-18 04:55 UTCGHSA enrichment
  18. 2026-09-18 00:44 UTCGHSA enrichment
  19. 2026-09-17 20:32 UTCEG score recompute
  20. 2026-09-17 20:32 UTCGHSA enrichment
  21. 2026-09-17 19:32 UTCEPSS rescore
  22. 2026-09-17 12:17 UTCGHSA enrichment
  23. 2026-09-17 08:05 UTCGHSA enrichment
  24. 2026-09-17 03:53 UTCGHSA enrichment
  25. 2026-09-16 23:42 UTCGHSA enrichment
Show 75 more
  1. 2026-09-16 19:30 UTCGHSA enrichment
  2. 2026-09-16 15:18 UTCEG score recompute
  3. 2026-09-16 15:18 UTCGHSA enrichment
  4. 2026-09-16 14:09 UTCEPSS rescore
  5. 2026-09-16 11:06 UTCGHSA enrichment
  6. 2026-09-16 06:54 UTCEG score recompute
  7. 2026-09-16 06:54 UTCGHSA enrichment
  8. 2026-09-16 05:15 UTCEPSS rescore
  9. 2026-09-16 02:43 UTCGHSA enrichment
  10. 2026-09-15 22:31 UTCGHSA enrichment
  11. 2026-09-15 18:19 UTCGHSA enrichment
  12. 2026-09-15 13:59 UTCGHSA enrichment
  13. 2026-09-15 09:47 UTCGHSA enrichment
  14. 2026-09-15 05:35 UTCEG score recompute
  15. 2026-09-15 05:35 UTCGHSA enrichment
  16. 2026-09-15 03:12 UTCEPSS rescore
  17. 2026-09-15 03:12 UTCEPSS rescore
  18. 2026-09-15 01:23 UTCGHSA enrichment
  19. 2026-09-14 21:11 UTCGHSA enrichment
  20. 2026-09-14 16:51 UTCGHSA enrichment
  21. 2026-09-14 12:39 UTCGHSA enrichment
  22. 2026-09-14 08:26 UTCGHSA enrichment
  23. 2026-09-14 04:14 UTCGHSA enrichment
  24. 2026-09-14 00:02 UTCGHSA enrichment
  25. 2026-09-13 19:51 UTCEG score recompute
  26. 2026-09-13 19:51 UTCGHSA enrichment
  27. 2026-09-13 15:39 UTCGHSA enrichment
  28. 2026-09-13 11:27 UTCGHSA enrichment
  29. 2026-09-13 07:15 UTCGHSA enrichment
  30. 2026-09-13 03:04 UTCGHSA enrichment
  31. 2026-09-12 22:52 UTCGHSA enrichment
  32. 2026-09-12 18:40 UTCEG score recompute
  33. 2026-09-12 18:40 UTCGHSA enrichment
  34. 2026-09-12 14:28 UTCGHSA enrichment
  35. 2026-09-12 10:16 UTCGHSA enrichment
  36. 2026-09-12 06:02 UTCGHSA enrichment
  37. 2026-09-12 01:50 UTCGHSA enrichment
  38. 2026-09-11 21:39 UTCGHSA enrichment
  39. 2026-09-11 17:27 UTCEG score recompute
  40. 2026-09-11 17:27 UTCGHSA enrichment
  41. 2026-09-11 14:53 UTCEPSS rescore
  42. 2026-09-11 14:53 UTCEPSS rescore
  43. 2026-09-11 13:15 UTCEG score recompute
  44. 2026-09-11 13:15 UTCGHSA enrichment
  45. 2026-09-11 09:03 UTCGHSA enrichment
  46. 2026-09-11 04:51 UTCGHSA enrichment
  47. 2026-09-11 00:39 UTCGHSA enrichment
  48. 2026-09-10 20:27 UTCGHSA enrichment
  49. 2026-09-10 16:16 UTCGHSA enrichment
  50. 2026-09-10 12:04 UTCEG score recompute
  51. 2026-09-10 12:03 UTCGHSA enrichment
  52. 2026-09-10 07:50 UTCGHSA enrichment
  53. 2026-09-10 03:38 UTCGHSA enrichment
  54. 2026-09-09 23:26 UTCGHSA enrichment
  55. 2026-09-09 17:18 UTCGHSA enrichment
  56. 2026-09-09 13:06 UTCGHSA enrichment
  57. 2026-09-09 08:55 UTCGHSA enrichment
  58. 2026-09-09 04:43 UTCGHSA enrichment
  59. 2026-09-09 00:32 UTCEG score recompute
  60. 2026-09-09 00:32 UTCGHSA enrichment
  61. 2026-09-08 22:01 UTCEPSS rescore
  62. 2026-09-08 20:19 UTCGHSA enrichment
  63. 2026-09-08 16:27 UTCGHSA enrichment
  64. 2026-09-08 11:52 UTCGHSA enrichment
  65. 2026-09-08 07:37 UTCGHSA enrichment
  66. 2026-09-08 03:25 UTCGHSA enrichment
  67. 2026-09-07 23:13 UTCGHSA enrichment
  68. 2026-09-07 19:01 UTCEG score recompute
  69. 2026-09-07 19:01 UTCGHSA enrichment
  70. 2026-09-07 14:49 UTCGHSA enrichment
  71. 2026-09-07 10:17 UTCGHSA enrichment
  72. 2026-09-07 06:05 UTCGHSA enrichment
  73. 2026-09-07 01:52 UTCGHSA enrichment
  74. 2026-09-06 21:38 UTCGHSA enrichment
  75. 2026-09-06 17:25 UTCEG score recompute

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-85440?
CVE-2026-85440 is a critical vulnerability published on September 3, 2026. 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…
When was CVE-2026-85440 disclosed?
CVE-2026-85440 was first published in the National Vulnerability Database on September 3, 2026, with the most recent update on September 8, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-85440 actively exploited?
CVE-2026-85440 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1% probability of exploitation in the next 30 days, which ranks it in the top 55.0% of all scored CVEs.
What is the CVSS score of CVE-2026-85440?
CVE-2026-85440 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2026-85440?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-85440, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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