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.
CVE-2026-76816
LOWPre-NVD 3.53.5—Trending — 3 sources updated this week
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%, top 93% of all CVEs by exploit prediction. 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%CVSS: 3.5Exploit: None knownExposed: 0
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 3.5
- EG Score
- 3.5(medium)
- EG Risk
- 16(Track)EG Risk 16/100SSVC: 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 computedSeverity35% × 45%Exploitation0% × 40%Automatability0% × 15%Action: Routine — remediate on your standard cadence. - EPSS PROB
- 0%
- EPSS %ILE
- 7%
- KEV
- Not listed
Published
August 24, 2026
Last Modified
August 25, 2026
References (3)
- security-advisories@githubhttps://github.com/netty/netty/commit/1b5abc6443b63726c72cdd285af2feb7ddbb8ff7
- security-advisories@githubhttps://github.com/netty/netty/commit/9e0519239108a69b7e9bbc5e9182ee139a0d7961
- security-advisories@githubhttps://github.com/netty/netty/security/advisories/GHSA-43fm-7cxg-hf3j
Weakness Classification(2)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 6× in last 7d / 6× 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.
- 2026-08-25 14:21 UTCEG score recompute
- 2026-08-25 14:00 UTCEG score recompute
- 2026-08-25 13:49 UTCEPSS rescore
- 2026-08-24 20:25 UTCEG score recompute
- 2026-08-24 20:01 UTCEG score recompute
- 2026-08-24 20:01 UTCMITRE cvelistV5first tracked
Related CVEs(same CWE)
Same CWE
10 shownCWE-20
- CVE-2005-0050EG 10.0EPSS p99HIGH
- CVE-2004-1019EG 10.0EPSS p94HIGH
- CVE-2004-0840EG 10.0EPSS p98HIGH
- CVE-2003-1425EG 10.0EPSS p96HIGH
- CVE-2003-1487EG 10.0EPSS p94HIGH
- CVE-2002-1874EG 10.0HIGH
- CVE-2002-2236EG 10.0EPSS p91HIGH
- CVE-2002-2365EG 10.0HIGH
- CVE-2002-1358EG 10.0EPSS p93HIGH
- CVE-2002-1359EG 10.0EPSS p100HIGH
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 in the National Vulnerability Database on August 24, 2026, with the most recent update on August 25, 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% probability of exploitation in the next 30 days, which ranks it in the top 93.1% of all scored CVEs.
What is the CVSS score of CVE-2026-76816?
CVE-2026-76816 has a CVSS v3 base score of 3.5 (NVD).
How do I remediate CVE-2026-76816?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-76816, 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.
Dependency Blast Radius
Explore the affected products and dependency analysis for CVE-2026-76816
Is Your Infrastructure Affected by CVE-2026-76816?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.