CVE-2018-18765

CRITICALNVD 9.19.1—
EchelonGraph scoreMEDIUM confidence

Score 9.1 from GitHub Security Advisory (severity: CRITICAL) published 2022-05-14. NVD baseline CVSS 9.1; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
9.1EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 2%CVSS: 9.1Exploit: None knownExposed: 0

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

An exploitable arbitrary memory read vulnerability exists in the MQTT packet-parsing functionality of Cesanta Mongoose 6.13. It is a heap-based buffer over-read in mg_mqtt_next_subscribe_topic. A specially crafted MQTT SUBSCRIBE packet can cause an arbitrary out-of-bounds memory read potentially resulting in information disclosure and denial of service. An attacker needs to send a specially crafted MQTT packet over the network to trigger this vulnerability.

CVSS v3
9.1
EG Score
9.1(medium)
EG Risk
46(Track)
EG Risk 46/100SSVC: 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
Severity91% × 45%
Exploitation2% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
2%
EPSS %ILE
78%
KEV
Not listed

Published

October 29, 2018

Last Modified

November 21, 2024

Advisory Details (2)

Auto-updated Jul 20, 2026
🔬 Proof of concept available. No patch confirmed yet.
generic

Thracky on X: "So I'm about 90% certain that CVE-2018-18765 is bs and should never have been assigned a CVE. Let's look at the writeup which includes the "vulnerable" code: https://t.co/KR0Y9gxDTc" / X

https://twitter.com/thracky/status/1059472674940993541
generic🟡 PoC Available

PoCbyMyself/mongoose6.13/mqtt/Cesanta Mongoose MQTT mg_mqtt_next_subscribe_topic heap buffer overflow.md at master · TiffanyBlue/PoCbyMyself · GitHub

https://github.com/TiffanyBlue/PoCbyMyself/blob/master/mongoose6.13/mqtt/Cesanta%20Mongoose%20MQTT%20mg_mqtt_next_subscribe_topic%20heap%20buffer%20overflow.md

Affected Packages

(4 across 4 ecosystems)
Debian:11(1)
PackageVulnerable rangeFixed inDependents
smplayer—18.5.0~ds1-1—
Debian:12(1)
PackageVulnerable rangeFixed inDependents
smplayer—18.5.0~ds1-1—
Debian:13(1)
PackageVulnerable rangeFixed inDependents
smplayer—18.5.0~ds1-1—
Debian:14(1)
PackageVulnerable rangeFixed inDependents
smplayer—18.5.0~ds1-1—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 7× in last 7d / 24× 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 143 total refreshes for this CVE.

  1. 2026-09-07 15:57 UTCEPSS rescore
  2. 2026-09-06 13:43 UTCEPSS rescore
  3. 2026-09-05 15:24 UTCEPSS rescore
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  1. 2026-08-07 16:23 UTCEPSS rescore
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  17. 2026-07-23 01:34 UTCEG score recompute
  18. 2026-07-22 22:14 UTCEG score recompute
  19. 2026-07-22 14:05 UTCEPSS rescore
  20. 2026-07-21 15:22 UTCEPSS rescore
  21. 2026-07-21 03:41 UTCOSV refresh
  22. 2026-07-20 17:04 UTCEPSS rescore
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  24. 2026-07-19 14:28 UTCEPSS rescore
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  47. 2026-07-03 22:56 UTCOSV refresh
  48. 2026-07-02 16:54 UTCEPSS rescore
  49. 2026-07-01 15:03 UTCEPSS rescore
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  51. 2026-06-30 23:20 UTCEPSS rescore
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  73. 2026-06-18 17:50 UTCEPSS rescore
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  75. 2026-06-17 17:50 UTCEPSS rescore

Frequently asked(5)

What is CVE-2018-18765?
CVE-2018-18765 is a critical vulnerability published on October 29, 2018. An exploitable arbitrary memory read vulnerability exists in the MQTT packet-parsing functionality of Cesanta Mongoose 6.13. It is a heap-based buffer over-read in mgmqttnextsubscribetopic. A specially crafted MQTT SUBSCRIBE packet can cause an arbitrary out-of-bounds memory read potentially…
When was CVE-2018-18765 disclosed?
CVE-2018-18765 was first published in the National Vulnerability Database on October 29, 2018, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2018-18765 actively exploited?
CVE-2018-18765 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 2% probability of exploitation in the next 30 days, which ranks it in the top 22.5% of all scored CVEs.
What is the CVSS score of CVE-2018-18765?
CVE-2018-18765 has a CVSS v3 base score of 9.1 (NVD).
How do I remediate CVE-2018-18765?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2018-18765, 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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