CVE-2026-76816

LOWPre-NVD 3.53.5—
EchelonGraph scoreMEDIUM confidence

This low-severity CVE scores 3.5 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.2% (6th 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
3.5EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.2%CVSS: 3.5Exploit: None knownExposed services: Not assessed

The CVE record names the fixed release — apply it.

Netty is an asynchronous, event-driven network application framework. Prior to versions 4.1.137.Final and 4.2.17.Final, MqttEncoder does not validate client identifiers, will topics, usernames, and PUBLISH topic names before encoding, allowing prohibited null bytes in MQTT UTF-8 string fields and potentially causing routing, access-control, or identity mismatches in downstream brokers. The vulnerability is exploitable when an application uses Netty's MQTT encoder to construct messages from user-controlled input. This issue is fixed in versions 4.1.137.Final and 4.2.17.Final.

CVSS v3
3.5
EG Score
3.5LOWmedium confidence
EG Risk
16
EG Risk 16/100CISA 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
Severity35% × 45%
Exploitation0% × 40%
Automatability0% × 15%
CISA SSVC: Track at every mission impact level.
Action: The CVE record names the fixed release. Apply it within your standard update timelines.
EPSS PROB
0.2%
EPSS %ILE
6th
KEV
Not listed

CISA SSVCTrack at every mission impact level.

The CVE record names the fixed release. Apply it within your standard update timelines.

Exploitation none (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

August 24, 2026

Last Modified

September 9, 2026

References (3)

Affected Packages

(3 across 3 ecosystems)
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
netty1:4.1.48-10 ... 1:4.1.48-9 (12 versions)
  • every version on: no fix on record
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
netty1:4.1.48-10 ... 1:4.1.48-16 (8 versions)
  • every version on: no fix on record
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
netty1:4.1.48-10 ... 1:4.1.48-16 (7 versions)
  • every version on: no fix on record
—

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 8× 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. 2026-10-09 20:07 UTCEPSS rescore
  2. 2026-10-09 04:41 UTCEG score recompute
  3. 2026-10-08 17:13 UTCEPSS rescore
  4. 2026-10-07 23:48 UTCEPSS rescore
  5. 2026-10-06 15:18 UTCEPSS rescore
  6. 2026-10-06 02:46 UTCEG score recompute
  7. 2026-10-05 17:43 UTCEPSS rescore
  8. 2026-10-04 23:22 UTCEPSS rescore
  9. 2026-10-03 14:26 UTCEPSS rescore
  10. 2026-10-03 04:08 UTCEG score recompute
  11. 2026-10-01 19:50 UTCEPSS rescore
  12. 2026-09-30 06:59 UTCEG score recompute
  13. 2026-09-29 15:24 UTCEPSS rescore
  14. 2026-09-28 13:52 UTCEPSS rescore
  15. 2026-09-27 13:48 UTCEPSS rescore
  16. 2026-09-27 02:56 UTCEG score recompute
  17. 2026-09-26 15:59 UTCEPSS rescore
  18. 2026-09-26 00:28 UTCEPSS rescore
  19. 2026-09-24 14:04 UTCEPSS rescore
  20. 2026-09-24 06:00 UTCEG score recompute
  21. 2026-09-23 17:54 UTCEPSS rescore
  22. 2026-09-22 16:01 UTCEPSS rescore
  23. 2026-09-21 21:09 UTCEPSS rescore
  24. 2026-09-21 09:04 UTCEG score recompute
  25. 2026-09-20 20:16 UTCEPSS rescore
Show 32 more
  1. 2026-09-18 19:28 UTCEPSS rescore
  2. 2026-09-18 12:08 UTCEG score recompute
  3. 2026-09-16 14:08 UTCEPSS rescore
  4. 2026-09-16 05:15 UTCEPSS rescore
  5. 2026-09-15 15:11 UTCEG score recompute
  6. 2026-09-15 03:12 UTCEPSS rescore
  7. 2026-09-12 18:14 UTCEG score recompute
  8. 2026-09-12 15:02 UTCEPSS rescore
  9. 2026-09-11 14:53 UTCEPSS rescore
  10. 2026-09-10 09:35 UTCEPSS rescore
  11. 2026-09-09 01:21 UTCEG score recompute
  12. 2026-09-08 22:01 UTCEPSS rescore
  13. 2026-09-06 13:48 UTCEPSS rescore
  14. 2026-09-06 02:13 UTCEG score recompute
  15. 2026-09-04 05:07 UTCEPSS rescore
  16. 2026-09-03 05:18 UTCEG score recompute
  17. 2026-09-02 14:12 UTCEPSS rescore
  18. 2026-09-01 13:54 UTCEPSS rescore
  19. 2026-08-31 08:20 UTCEG score recompute
  20. 2026-08-30 19:18 UTCEPSS rescore
  21. 2026-08-30 19:17 UTCEPSS rescore
  22. 2026-08-30 01:22 UTCEPSS rescore
  23. 2026-08-28 21:42 UTCEPSS rescore
  24. 2026-08-28 11:21 UTCEG score recompute
  25. 2026-08-27 14:25 UTCEPSS rescore
  26. 2026-08-26 14:47 UTCEPSS rescore
  27. 2026-08-25 14:21 UTCEG score recompute
  28. 2026-08-25 14:00 UTCEG score recompute
  29. 2026-08-25 13:49 UTCEPSS rescore
  30. 2026-08-24 20:25 UTCEG score recompute
  31. 2026-08-24 20:01 UTCEG score recompute
  32. 2026-08-24 20:01 UTCMITRE cvelistV5first tracked

Related CVEs(same product + same CWE)

Frequently asked(5)

What is CVE-2026-76816?
CVE-2026-76816 is a low vulnerability published on August 24, 2026. Netty is an asynchronous, event-driven network application framework. Prior to versions 4.1.137.Final and 4.2.17.Final, MqttEncoder does not validate client identifiers, will topics, usernames, and PUBLISH topic names before encoding, allowing prohibited null bytes in MQTT UTF-8 string fields and…
When was CVE-2026-76816 disclosed?
CVE-2026-76816 was first published on August 24, 2026, with the most recent update on September 9, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-76816 actively exploited?
CVE-2026-76816 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.2% probability of exploitation in the next 30 days (6th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-76816?
CVE-2026-76816 has a CVSS base score of 3.5 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-76816?
The CVE record for CVE-2026-76816 names the fix: "This issue is fixed in versions 4.1.137.Final and 4.2.17.Final."

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-76816

Explore →

Is Your Infrastructure Affected by CVE-2026-76816?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.

Book a Demo →Browse All CVEs