CVE-2026-44248

HIGHNVD 7.55.3▼
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 5.3 under NVD CVSS v3. EPSS exploit probability: 0.4%, top 72% 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, nvd
7.5
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 7.5Exploit: NoneExposed: 0

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

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.

CVSS v3
7.5
EG Score
5.3(medium)
EPSS
39.2%
KEV
Not listed

Published

May 13, 2026

Last Modified

July 21, 2026

Advisory Details (1)

Auto-updated May 18, 2026
Patch available. Sources: github.
github Patch Available

MQTT: Resource exhaustion in MqttDecoder · Advisory · netty/netty · GitHub

https://github.com/netty/netty/security/advisories/GHSA-jfg9-48mv-9qgx

Vendor 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)
PackageVulnerable rangeFixed inDependents
io.netty:netty-codec-mqtt4.1.0.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 8× in last 7d / 36× 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. 2026-07-22 14:08 UTCEPSS rescore
  2. 2026-07-21 15:24 UTCEPSS rescore
  3. 2026-07-20 17:08 UTCEPSS rescore
  4. 2026-07-19 14:31 UTCEPSS rescore
  5. 2026-07-19 02:29 UTCEPSS rescore
  6. 2026-07-18 10:04 UTCEPSS rescore
  7. 2026-07-18 02:29 UTCOSV refresh
  8. 2026-07-16 17:03 UTCEPSS rescore
  9. 2026-07-15 16:57 UTCEPSS rescore
  10. 2026-07-15 02:25 UTCNVD updateCVSS v3 → 7.5 · severity → HIGH
  11. 2026-07-15 02:00 UTCEPSS rescore
  12. 2026-07-15 01:21 UTCMITRE cvelistV5CVSS v3 → 5.3 · severity → MEDIUM
  13. 2026-07-13 22:30 UTCEPSS rescore
  14. 2026-07-13 06:13 UTCEPSS rescore
  15. 2026-07-12 05:46 UTCEPSS rescore
  16. 2026-07-11 08:27 UTCEPSS rescore
  17. 2026-07-10 12:26 UTCNVD updateCVSS v3 → 7.5 · severity → HIGH
  18. 2026-07-10 12:12 UTCMITRE cvelistV5CVSS v3 → 5.3 · severity → MEDIUM
  19. 2026-07-09 19:10 UTCEPSS rescore
  20. 2026-07-08 15:16 UTCEPSS rescore
  21. 2026-07-07 13:46 UTCEPSS rescore
  22. 2026-07-06 16:27 UTCEPSS rescore
  23. 2026-07-06 02:23 UTCEPSS rescore
  24. 2026-07-05 02:30 UTCEPSS rescore
  25. 2026-07-04 06:31 UTCEPSS rescore
Show 59 more
  1. 2026-07-01 15:07 UTCEPSS rescore
  2. 2026-06-30 23:22 UTCEPSS rescore
  3. 2026-06-30 04:33 UTCNVD updateCVSS v3 → 7.5 · severity → HIGH
  4. 2026-06-29 14:06 UTCEPSS rescore
  5. 2026-06-28 14:07 UTCEPSS rescore
  6. 2026-06-28 04:56 UTCEPSS rescore
  7. 2026-06-27 03:08 UTCEPSS rescore
  8. 2026-06-25 13:49 UTCEPSS rescore
  9. 2026-06-25 13:49 UTCEPSS rescore
  10. 2026-06-24 14:05 UTCEPSS rescore
  11. 2026-06-23 21:33 UTCEPSS rescore
  12. 2026-06-22 14:25 UTCEPSS rescore
  13. 2026-06-22 14:25 UTCEPSS rescore
  14. 2026-06-21 14:56 UTCEPSS rescore
  15. 2026-06-21 14:56 UTCEPSS rescore
  16. 2026-06-21 01:59 UTCEPSS rescore
  17. 2026-06-19 19:25 UTCEPSS rescore
  18. 2026-06-18 17:52 UTCEPSS rescore
  19. 2026-06-18 17:52 UTCEPSS rescore
  20. 2026-06-17 17:53 UTCEPSS rescore
  21. 2026-06-16 17:52 UTCEPSS rescore
  22. 2026-06-15 17:49 UTCEPSS rescore
  23. 2026-06-13 23:00 UTCEPSS rescore
  24. 2026-06-12 23:12 UTCEPSS rescore
  25. 2026-06-12 23:12 UTCEPSS rescore
  26. 2026-06-11 14:00 UTCEPSS rescore
  27. 2026-06-10 22:18 UTCEPSS rescore
  28. 2026-06-10 13:22 UTCEPSS rescore
  29. 2026-06-10 13:22 UTCEPSS rescore
  30. 2026-06-08 14:17 UTCEPSS rescore
  31. 2026-06-08 14:17 UTCEPSS rescore
  32. 2026-06-07 15:25 UTCEPSS rescore
  33. 2026-06-07 15:25 UTCEPSS rescore
  34. 2026-06-06 13:47 UTCEPSS rescore
  35. 2026-06-06 13:47 UTCEPSS rescore
  36. 2026-06-05 22:47 UTCEPSS rescore
  37. 2026-06-05 06:10 UTCEPSS rescore
  38. 2026-06-05 06:10 UTCEPSS rescore
  39. 2026-06-04 13:12 UTCEPSS rescore
  40. 2026-06-04 13:12 UTCEPSS rescore
  41. 2026-06-02 20:13 UTCEPSS rescore
  42. 2026-06-01 13:52 UTCEPSS rescore
  43. 2026-06-01 13:52 UTCEPSS rescore
  44. 2026-05-31 22:30 UTCEPSS rescore
  45. 2026-05-31 22:30 UTCEPSS rescore
  46. 2026-05-31 00:16 UTCEPSS rescore
  47. 2026-05-31 00:16 UTCEPSS rescore
  48. 2026-05-29 13:44 UTCEPSS rescore
  49. 2026-05-29 13:44 UTCEPSS rescore
  50. 2026-05-28 13:44 UTCEPSS rescore
  51. 2026-05-28 13:44 UTCEPSS rescore
  52. 2026-05-27 13:40 UTCEPSS rescore
  53. 2026-05-27 13:40 UTCEPSS rescore
  54. 2026-05-26 13:44 UTCEPSS rescore
  55. 2026-05-26 07:18 UTCEPSS rescore
  56. 2026-05-21 22:43 UTCEPSS rescore
  57. 2026-05-20 22:38 UTCEPSS rescore
  58. 2026-05-20 12:26 UTCEG score recompute
  59. 2026-05-20 11:22 UTCEPSS rescore

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-44248?
CVE-2026-44248 is a high vulnerability published on May 13, 2026. 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…
When was CVE-2026-44248 disclosed?
CVE-2026-44248 was first published in the National Vulnerability Database on May 13, 2026, with the most recent update on July 21, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-44248 actively exploited?
CVE-2026-44248 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 39.2% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-44248?
CVE-2026-44248 has a CVSS v3 base score of 7.5 (NVD). EchelonGraph synthesises NVD + CISA KEV + FIRST EPSS + GHSA into a combined EG score of 5.3.
How do I remediate CVE-2026-44248?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-44248, 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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