CVE-2026-44248

HIGHNVD 7.57.5
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to NVD's CVSS score.

This high-severity CVE scores 7.5 under NVD CVSS v3. EPSS exploit probability: 0.7% (53rd percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.

Triggered by: Headline CVSS from NVD CVSS v3
Sources: EPSS, NVD CVSS v3
Trending — 3 sources updated this week
7.5EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines at low or medium mission impact and sooner than that at high (the SSVC decision on this page).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.7%CVSS: 7.5Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

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
7.5HIGHmedium confidence
EG Risk
49
EG Risk 49/100

EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.

How it’s computed (value × EchelonGraph’s weight)
Severity75% × 45%
Impact severity (EG Severity): CVSS 7.5 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.7% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability100% × 15%
CISA's SSVC Automatable value: yes (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Attend at high (mission-essential systems).
Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
EPSS PROB
0.7%
EPSS %ILE
53rd
KEV
Not listed

What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)

The EG score (7.5): severity, escalated by confirmed exploitation. This CVE's 7.5 is its impact severity (EG Severity), not escalated.

EG Severity
7.5 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.NVD CVSS v3 · CVSS v3.0 or v3.1
EG Likelihood
0.7% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-17). FIRST's exploitation probability, not an EchelonGraph model.
Confirmed exploitation
None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
EG Priority
SSVC Track at medium mission impactTrack at low or medium mission impact; Attend at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; 60 days if it is not.Each input and its source: the SSVC and BOD 26-04 blocks below.

SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Attend at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)14 days if the affected system is publicly exposed; 60 days if it is not.

In CISA KEV no (CISA's KEV catalog) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

May 13, 2026

Last Modified

September 11, 2026

Advisory Details (1)

Auto-updated May 18, 2026
Patch available. Sources: github.
GitHub advisoryMentions a patch (unverified)

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

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

Patch Availability(1)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
redhatnetty-codec-mqtt2026-09-10redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(5 across 5 ecosystems)
Debian:11(1)
PackageVulnerable rangeFix by version rangeDependents
netty1:4.1.48-10 ... 1:4.1.48-9 (16 versions)
  • every version on: no fix on record
—
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
—
Maven(1)
PackageVulnerable rangeFix by version rangeDependents
io.netty:netty-codec-mqtt4.1.0.Beta1 ... 4.1.99.Final (148 versions)
  • 4.2.0.Alpha1 up to 4.2.13.Final: fixed in 4.2.13.Final
  • every version up to 4.1.133.Final: fixed in 4.1.133.Final
—

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 10× in last 7d / 32× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. 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. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

Showing the most recent 100 of 222 refreshes on record for this CVE.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. None are among the latest 100 rows. The 122 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-21 16:33 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  2. 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  3. 2026-10-19 16:32 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  4. 2026-10-18 16:32 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  5. 2026-10-18 03:39 UTCEG score recompute
  6. 2026-10-17 16:34 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  7. 2026-10-17 14:01 UTCEG score recompute
  8. 2026-10-17 14:01 UTCVendor advisory
  9. 2026-10-16 16:42 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  10. 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  11. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  12. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  13. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  14. 2026-10-12 16:05 UTCEG score recompute
  15. 2026-10-11 19:47 UTCEG score recompute
  16. 2026-10-11 17:02 UTCEG score recompute
  17. 2026-10-11 14:27 UTCEG score recompute
  18. 2026-10-11 13:48 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  19. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  20. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  21. 2026-10-08 17:12 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  22. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  23. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  24. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  25. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
Show 75 more
  1. 2026-10-03 14:25 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  2. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  3. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  4. 2026-09-30 07:28 UTCOSV refresh
  5. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  6. 2026-09-26 15:58 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  7. 2026-09-23 17:53 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  8. 2026-09-20 20:15 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  9. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  10. 2026-09-17 19:31 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  11. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  12. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  13. 2026-09-13 16:47 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  14. 2026-09-12 15:01 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  15. 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  16. 2026-09-11 13:25 UTCVendor advisory
  17. 2026-09-11 12:21 UTCEG score recompute
  18. 2026-09-11 12:21 UTCVendor advisory
  19. 2026-09-11 09:37 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  20. 2026-09-11 08:23 UTCOSV refresh
  21. 2026-09-10 09:34 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  22. 2026-09-08 22:00 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  23. 2026-09-07 16:01 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  24. 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  25. 2026-09-04 05:06 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  26. 2026-09-02 14:12 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  27. 2026-09-01 13:54 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  28. 2026-08-30 19:17 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  29. 2026-08-30 01:22 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  30. 2026-08-28 21:41 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  31. 2026-08-27 14:25 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  32. 2026-08-26 14:46 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  33. 2026-08-25 13:49 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  34. 2026-08-23 17:50 UTCEG score recompute
  35. 2026-08-23 17:50 UTCVendor advisory
  36. 2026-08-23 00:19 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  37. 2026-08-22 02:05 UTCEG score recompute
  38. 2026-08-22 02:05 UTCVendor advisory
  39. 2026-08-21 23:49 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  40. 2026-08-20 22:55 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  41. 2026-08-20 19:47 UTCEG score recompute
  42. 2026-08-20 19:47 UTCVendor advisory
  43. 2026-08-19 17:04 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  44. 2026-08-18 13:48 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  45. 2026-08-17 13:47 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  46. 2026-08-17 10:30 UTCEG score recompute
  47. 2026-08-17 10:30 UTCVendor advisory
  48. 2026-08-16 14:56 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  49. 2026-08-16 04:02 UTCEG score recompute
  50. 2026-08-16 04:02 UTCVendor advisory
  51. 2026-08-16 02:14 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  52. 2026-08-15 01:30 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  53. 2026-08-15 00:53 UTCVendor advisory
  54. 2026-08-14 13:41 UTCVendor advisory
  55. 2026-08-14 02:30 UTCEG score recompute
  56. 2026-08-14 02:30 UTCVendor advisory
  57. 2026-08-13 22:00 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  58. 2026-08-13 03:00 UTCVendor advisory
  59. 2026-08-12 15:49 UTCEG score recompute
  60. 2026-08-12 15:49 UTCVendor advisory
  61. 2026-08-12 13:51 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  62. 2026-08-11 15:27 UTCEG score recompute
  63. 2026-08-11 15:27 UTCVendor advisory
  64. 2026-08-11 13:43 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  65. 2026-08-11 00:56 UTCEG score recompute
  66. 2026-08-11 00:56 UTCVendor advisory
  67. 2026-08-11 00:00 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  68. 2026-08-10 11:30 UTCVendor advisory
  69. 2026-08-10 00:17 UTCEG score recompute
  70. 2026-08-10 00:17 UTCVendor advisory
  71. 2026-08-09 13:46 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  72. 2026-08-09 13:05 UTCVendor advisory
  73. 2026-08-09 01:54 UTCEG score recompute
  74. 2026-08-09 01:54 UTCVendor advisory
  75. 2026-08-08 16:37 UTCEPSS rescoreEPSS 0.5% · 39th percentile

Frequently asked(5)

What is CVE-2026-44248?
CVE-2026-44248 is a high-severity vulnerability; its CVE record was 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 the CVE record for CVE-2026-44248 published?
The CVE record for CVE-2026-44248 was published on May 13, 2026. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of September 11, 2026; the record at its source may have been updated since.
Is CVE-2026-44248 actively exploited?
CVE-2026-44248 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.7% probability of exploitation in the next 30 days (53rd percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-44248?
CVE-2026-44248 has a CVSS v3 base score of 7.5 (NVD).
How do I remediate CVE-2026-44248?
A fix for CVE-2026-44248 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-44248 are linked in the Vendor Advisories panel on this page.

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