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 63% 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 — 3 sources updated 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
37%
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(8)

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

Patch Availability(2)

Vendor / EcosystemFixed in / PatchReleasedSource
redhatdevspaces/pluginregistry-rhel9:17877597232026-09-01redhat
redhatnetty-codec-http2026-08-13redhat

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 12× in last 7d / 93× 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 153 total refreshes for this CVE.

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

Related CVEs(same vendor + same CWE)

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 63.1% 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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