CVE-2026-73863

HIGHPre-NVD 7.07.0—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.0 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.4% (26th percentile of EPSS-scored CVEs). GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
Elevated
7.0EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.4%CVSS: 7.0Exploit: Elevated riskExposed services: Not assessed

A fix is available — apply it.

NanoMQ is an MQTT broker. Prior to 0.24.14, NanoMQ's broker-side MQTT v5 nmq_subinfo_decode() function in nng/src/sp/protocol/mqtt/mqtt_parser.c reuses len_of_varint from the outer Properties Length while parsing each SUBSCRIPTION_IDENTIFIER. A remote client can send a SUBSCRIBE packet with a multi-byte Properties Length and repeated subscription identifiers, causing get_var_integer() to begin at an incorrect offset and read beyond the heap message buffer. The flaw is reachable through the broker receive path and can crash the broker, while the separately reported topic-option off-by-one occurs later and is not this vulnerability. This issue is fixed in version 0.24.14.

CVSS v3
7.0
EG Score
7.0HIGHmedium confidence
EG Risk
48
EG Risk 48/100CISA SSVC

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
Severity70% × 45%
Exploitation40% × 40%
Automatability0% × 15%
CISA SSVC: Track at low or medium mission impact; Track* at high (mission-essential systems).
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.4%
EPSS %ILE
26th
KEV
Not listed

CISA SSVCTrack at low or medium mission impact; Track* at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines.

Exploitation public PoC (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

September 18, 2026

Last Modified

September 24, 2026

Advisory Details (4)

Auto-updated Sep 18, 2026
🔬 Proof of concept available. Patch available. Sources: github, github_pr, github_commit, github_release.
github_release Patch Available

NanoMQ 0.24.14

Patch available: nanomq/nanomq 0.24.14

https://github.com/nanomq/nanomq/releases/tag/0.24.14
github_commit Patch Available

commit f888fe39d669 (nanomq/NanoNNG)

Patch available: nanomq/NanoNNG 0.24.14 (contains commit f888fe39d669)

https://github.com/nanomq/NanoNNG/commit/f888fe39d6691b253ff9aee598ce58bbe449ab6f
github_pr Patch Available

multipe safe checker added

Patch available: nanomq/NanoNNG 0.24.14 (PR #1518 merged 2026-05-20)

https://github.com/nanomq/NanoNNG/pull/1518
github Patch Available🟡 PoC Available

Heap-Buffer-Overflow in `nmq_subinfo_decode()` During MQTT v5 SUBSCRIBE Parsing · Advisory · nanomq/nanomq · GitHub

https://github.com/nanomq/nanomq/security/advisories/GHSA-pf97-vm7h-q84m

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 13× in last 7d / 34× 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.

  1. 2026-10-05 03:07 UTCEG score recompute
  2. 2026-10-04 23:22 UTCEPSS rescore
  3. 2026-10-03 17:36 UTCEG score recompute
  4. 2026-10-03 14:26 UTCEPSS rescore
  5. 2026-10-02 19:22 UTCEG score recompute
  6. 2026-10-01 21:08 UTCEG score recompute
  7. 2026-10-01 19:50 UTCEPSS rescore
  8. 2026-09-30 22:55 UTCEG score recompute
  9. 2026-09-30 00:41 UTCEG score recompute
  10. 2026-09-29 15:24 UTCEPSS rescore
  11. 2026-09-29 02:19 UTCEG score recompute
  12. 2026-09-28 15:11 UTCEG score recompute
  13. 2026-09-28 13:52 UTCEPSS rescore
  14. 2026-09-27 16:54 UTCEG score recompute
  15. 2026-09-27 13:48 UTCEPSS rescore
  16. 2026-09-26 18:41 UTCEG score recompute
  17. 2026-09-26 15:59 UTCEPSS rescore
  18. 2026-09-26 07:34 UTCEG score recompute
  19. 2026-09-26 00:28 UTCEPSS rescore
  20. 2026-09-25 08:31 UTCEG score recompute
  21. 2026-09-24 21:24 UTCEG score recompute
  22. 2026-09-24 21:12 UTCEG score recompute
  23. 2026-09-24 18:08 UTCEG score recompute
  24. 2026-09-23 19:53 UTCEG score recompute
  25. 2026-09-23 17:54 UTCEPSS rescore
Show 9 more
  1. 2026-09-22 21:40 UTCEG score recompute
  2. 2026-09-21 23:24 UTCEG score recompute
  3. 2026-09-21 21:09 UTCEPSS rescore
  4. 2026-09-21 01:10 UTCEG score recompute
  5. 2026-09-20 20:16 UTCEPSS rescore
  6. 2026-09-20 02:50 UTCEG score recompute
  7. 2026-09-18 17:26 UTCEG score recompute
  8. 2026-09-18 16:29 UTCEG score recompute
  9. 2026-09-18 16:29 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-73863?
CVE-2026-73863 is a high vulnerability published on September 18, 2026. NanoMQ is an MQTT broker. Prior to 0.24.14, NanoMQ's broker-side MQTT v5 nmqsubinfodecode() function in nng/src/sp/protocol/mqtt/mqttparser.c reuses lenofvarint from the outer Properties Length while parsing each SUBSCRIPTIONIDENTIFIER. A remote client can send a SUBSCRIBE packet with a multi-byte…
When was CVE-2026-73863 disclosed?
CVE-2026-73863 was first published on September 18, 2026, with the most recent update on September 24, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-73863 actively exploited?
CVE-2026-73863 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.4% probability of exploitation in the next 30 days (26th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-73863?
CVE-2026-73863 has a CVSS base score of 7.0 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-73863?
A fix for CVE-2026-73863 is available: update to the fixed version the vendor names in its advisory.

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