CVE-2026-55831

HIGHPre-NVD 7.57.5—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.5 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.4%, top 62% 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
Trending — Patch released this weekElevated
7.5EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 7.5Exploit: Elevated riskExposed: 0

A fix is available — apply it.

Netty is a network application framework for development of protocol servers and clients. Prior to 4.1.136.Final and 4.2.16.Final, Netty's SPDY SETTINGS decoder accepts a peer-declared SETTINGS entry count up to the 24-bit frame-length limit and materializes every unique setting ID in DefaultSpdySettingsFrame, allowing a remote SPDY/3.1 peer to send a syntactically valid roughly 2 MiB SETTINGS frame that creates 262144 map entries and amplifies network input into heap growth and ordered-map insertion work. This issue is fixed in versions 4.1.136.Final and 4.2.16.Final.

CVSS v3
7.5
EG Score
7.5(medium)
EG Risk
65(Attend)
EG Risk 65/100SSVC: Attend

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
Severity75% × 45%
Exploitation40% × 40%
Automatability100% × 15%
Action: Remediate soon — notable exploitation risk.
EPSS PROB
0%
EPSS %ILE
38%
KEV
Not listed

Published

July 20, 2026

Last Modified

July 23, 2026

Advisory Details (5)

Auto-updated Jul 21, 2026
🔬 Proof of concept available. Patch available. Sources: github_commit, github_release, github.
github Patch Available🟡 PoC Available

Netty SPDY SETTINGS frame count materializes unbounded settings map · Advisory · netty/netty · GitHub

https://github.com/netty/netty/security/advisories/GHSA-6jqx-86gh-f27w
github_release Patch Available

netty-4.2.16.Final

Patch available: netty/netty netty-4.2.16.Final

https://github.com/netty/netty/releases/tag/netty-4.2.16.Final
github_release Patch Available

netty-4.1.136.Final

Patch available: netty/netty netty-4.1.136.Final

https://github.com/netty/netty/releases/tag/netty-4.1.136.Final
github_commit Patch Available

commit bb2ff68a1fb7 (netty/netty)

Patch available: netty/netty netty-4.1.136.Final (contains commit bb2ff68a1fb7)

https://github.com/netty/netty/commit/bb2ff68a1fb71cb4b0eb9a9e17b66c52aff680c6
github_commit Patch Available

commit 5b68c61f37aa (netty/netty)

Patch available: netty/netty netty-4.2.16.Final (contains commit 5b68c61f37aa)

https://github.com/netty/netty/commit/5b68c61f37aa4a3045cba624cbea239655c9003b

Vendor Advisories for CVE-2026-55831(11)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(4)

Vendor / EcosystemFixed in / PatchReleasedSource
redhatcryostat/jfr-datasource-rhel9:4.2.0-142026-09-16redhat
redhatnetty-codec-http2026-09-10redhat
redhatrhoai/odh-trustyai-service-rhel9:17881986812026-09-08redhat
redhatdevspaces/pluginregistry-rhel9:17877597232026-09-01redhat

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 rangeFixed inDependents
netty1:4.1.48-10 ... 1:4.1.48-9 (16 versions)——
Debian:12(1)
PackageVulnerable rangeFixed inDependents
netty1:4.1.48-10 ... 1:4.1.48-9 (12 versions)——
Debian:13(1)
PackageVulnerable rangeFixed inDependents
netty1:4.1.48-10 ... 1:4.1.48-16 (8 versions)——
Debian:14(1)
PackageVulnerable rangeFixed inDependents
netty1:4.1.48-10 ... 1:4.1.48-16 (7 versions)——
Maven(1)
PackageVulnerable rangeFixed inDependents
io.netty:netty-codec-http4.1.0.Final ... 4.1.99.Final (136 versions)4.1.136.Final—

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 20× in last 7d / 82× 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.

Showing the most recent 100 of 181 total refreshes for this CVE.

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

Frequently asked(5)

What is CVE-2026-55831?
CVE-2026-55831 is a high vulnerability published on July 20, 2026. Netty is a network application framework for development of protocol servers and clients. Prior to 4.1.136.Final and 4.2.16.Final, Netty's SPDY SETTINGS decoder accepts a peer-declared SETTINGS entry count up to the 24-bit frame-length limit and materializes every unique setting ID in…
When was CVE-2026-55831 disclosed?
CVE-2026-55831 was first published in the National Vulnerability Database on July 20, 2026, with the most recent update on July 23, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-55831 actively exploited?
CVE-2026-55831 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 62.4% of all scored CVEs.
What is the CVSS score of CVE-2026-55831?
CVE-2026-55831 has a CVSS v3 base score of 7.5 (NVD).
How do I remediate CVE-2026-55831?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-55831, 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

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