Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, the MQTT 5 header Properties section is parsed and buffered before any message size limit is applied. Specifically, in MqttDecoder, the decodeVariableHeader() method is called before the bytesRemainingBeforeVariableHeader > maxBytesInMessage check. The decodeVariableHeader() can call other methods which will call decodeProperties(). Effectively, Netty does not apply any limits to the size of the properties being decoded. Additionally, because MqttDecoder extends ReplayingDecoder, Netty will repeatedly re-parse the enormous Properties sections and buffer the bytes in memory, until the entire thing parses to completion. This can cause high resource usage in both CPU and memory. This vulnerability is fixed in 4.2.13.Final and 4.1.133.Final.
CVE-2026-44248
This high-severity CVE scores 7.5 under NVD CVSS v3. EPSS exploit probability: 0.5%, top 61% 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).
- High severity, but no confirmed exploitation yet
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 7.5
- EG Score
- 7.5(medium)
- EG Risk
- 49(Track)EG Risk 49/100SSVC: 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 computedSeverity75% × 45%Exploitation0% × 40%Automatability100% × 15%Action: Routine — remediate on your standard cadence. - EPSS PROB
- 0%
- EPSS %ILE
- 39%
- KEV
- Not listed
Published
May 13, 2026
Last Modified
July 21, 2026
Advisory Details (1)
Auto-updated May 18, 2026MQTT: Resource exhaustion in MqttDecoder · Advisory · netty/netty · GitHub
https://github.com/netty/netty/security/advisories/GHSA-jfg9-48mv-9qgxVendor Advisories for CVE-2026-44248(2)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Affected Packages
(1 across 1 ecosystem)
Maven(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| io.netty:netty-codec-mqtt | 4.1.0.Beta1 ... 4.1.99.Final (148 versions) | 4.1.133.Final | — |
Weakness Classification(2)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 9× in last 7d / 37× 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.
- 2026-07-26 14:54 UTCEPSS rescore
- 2026-07-26 14:54 UTCEPSS rescore
- 2026-07-25 14:18 UTCEPSS rescore
- 2026-07-24 14:17 UTCEPSS rescore
- 2026-07-23 14:18 UTCEPSS rescore
- 2026-07-23 03:14 UTCEG score recompute▲ 2.20
- 2026-07-22 14:08 UTCEPSS rescore
- 2026-07-21 15:24 UTCEPSS rescore
- 2026-07-20 17:08 UTCEPSS rescore
- 2026-07-19 14:31 UTCEPSS rescore
- 2026-07-19 02:29 UTCEPSS rescore
- 2026-07-18 10:04 UTCEPSS rescore
- 2026-07-18 02:29 UTCOSV refresh
- 2026-07-16 17:03 UTCEPSS rescore
- 2026-07-15 16:57 UTCEPSS rescore
- 2026-07-15 02:25 UTCNVD updateCVSS v3 → 7.5 · severity → HIGH
- 2026-07-15 02:00 UTCEPSS rescore
- 2026-07-15 01:21 UTCMITRE cvelistV5CVSS v3 → 5.3 · severity → MEDIUM
- 2026-07-13 22:30 UTCEPSS rescore
- 2026-07-13 06:13 UTCEPSS rescore
- 2026-07-12 05:46 UTCEPSS rescore
- 2026-07-11 08:27 UTCEPSS rescore
- 2026-07-10 12:26 UTCNVD updateCVSS v3 → 7.5 · severity → HIGH
- 2026-07-10 12:12 UTCMITRE cvelistV5CVSS v3 → 5.3 · severity → MEDIUM
- 2026-07-09 19:10 UTCEPSS rescore
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- 2026-07-08 15:16 UTCEPSS rescore
- 2026-07-07 13:46 UTCEPSS rescore
- 2026-07-06 16:27 UTCEPSS rescore
- 2026-07-06 02:23 UTCEPSS rescore
- 2026-07-05 02:30 UTCEPSS rescore
- 2026-07-04 06:31 UTCEPSS rescore
- 2026-07-01 15:07 UTCEPSS rescore
- 2026-06-30 23:22 UTCEPSS rescore
- 2026-06-30 04:33 UTCNVD updateCVSS v3 → 7.5 · severity → HIGH
- 2026-06-29 14:06 UTCEPSS rescore
- 2026-06-28 14:07 UTCEPSS rescore
- 2026-06-28 04:56 UTCEPSS rescore
- 2026-06-27 03:08 UTCEPSS rescore
- 2026-06-25 13:49 UTCEPSS rescore
- 2026-06-25 13:49 UTCEPSS rescore
- 2026-06-24 14:05 UTCEPSS rescore
- 2026-06-23 21:33 UTCEPSS rescore
- 2026-06-22 14:25 UTCEPSS rescore
- 2026-06-22 14:25 UTCEPSS rescore
- 2026-06-21 14:56 UTCEPSS rescore
- 2026-06-21 14:56 UTCEPSS rescore
- 2026-06-21 01:59 UTCEPSS rescore
- 2026-06-19 19:25 UTCEPSS rescore
- 2026-06-18 17:52 UTCEPSS rescore
- 2026-06-18 17:52 UTCEPSS rescore
- 2026-06-17 17:53 UTCEPSS rescore
- 2026-06-16 17:52 UTCEPSS rescore
- 2026-06-15 17:49 UTCEPSS rescore
- 2026-06-13 23:00 UTCEPSS rescore
- 2026-06-12 23:12 UTCEPSS rescore
- 2026-06-12 23:12 UTCEPSS rescore
- 2026-06-11 14:00 UTCEPSS rescore
- 2026-06-10 22:18 UTCEPSS rescore
- 2026-06-10 13:22 UTCEPSS rescore
- 2026-06-10 13:22 UTCEPSS rescore
- 2026-06-08 14:17 UTCEPSS rescore
- 2026-06-08 14:17 UTCEPSS rescore
- 2026-06-07 15:25 UTCEPSS rescore
- 2026-06-07 15:25 UTCEPSS rescore
- 2026-06-06 13:47 UTCEPSS rescore
- 2026-06-06 13:47 UTCEPSS rescore
- 2026-06-05 22:47 UTCEPSS rescore
- 2026-06-05 06:10 UTCEPSS rescore
- 2026-06-05 06:10 UTCEPSS rescore
- 2026-06-04 13:12 UTCEPSS rescore
- 2026-06-04 13:12 UTCEPSS rescore
- 2026-06-02 20:13 UTCEPSS rescore
- 2026-06-01 13:52 UTCEPSS rescore
- 2026-06-01 13:52 UTCEPSS rescore
- 2026-05-31 22:30 UTCEPSS rescore
- 2026-05-31 22:30 UTCEPSS rescore
- 2026-05-31 00:16 UTCEPSS rescore
- 2026-05-31 00:16 UTCEPSS rescore
- 2026-05-29 13:44 UTCEPSS rescore
- 2026-05-29 13:44 UTCEPSS rescore
- 2026-05-28 13:44 UTCEPSS rescore
- 2026-05-28 13:44 UTCEPSS rescore
- 2026-05-27 13:40 UTCEPSS rescore
- 2026-05-27 13:40 UTCEPSS rescore
- 2026-05-26 13:44 UTCEPSS rescore
- 2026-05-26 07:18 UTCEPSS rescore
- 2026-05-21 22:43 UTCEPSS rescore
- 2026-05-20 22:38 UTCEPSS rescore
- 2026-05-20 12:26 UTCEG score recompute
- 2026-05-20 11:22 UTCEPSS rescore
Related CVEs(same CWE)
Same CWE
10 shownCWE-400 · CWE-770
- CVE-2004-1464NVD 5.9EG 9.0 KEVEPSS p92CRITICAL
- CVE-2010-3705EG 8.3HIGH
- CVE-2006-1364NVD 7.5EG 8.2EPSS p99HIGH
- CVE-2008-5180NVD 5.3EG 7.9EPSS p99HIGH
- CVE-2012-0024EG 7.8HIGH
- CVE-2011-3192EG 7.8EPSS p100HIGH
- CVE-2010-4686EG 7.8HIGH
- CVE-2010-4671EG 7.8HIGH
- CVE-2009-2054EG 7.8HIGH
- CVE-2009-2726EG 7.8EPSS p93HIGH
Frequently asked(5)
What is CVE-2026-44248?
When was CVE-2026-44248 disclosed?
Is CVE-2026-44248 actively exploited?
What is the CVSS score of CVE-2026-44248?
How do I remediate CVE-2026-44248?
Dependency Blast Radius
See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-44248
Is Your Infrastructure Affected by CVE-2026-44248?
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