CVE-2026-56819

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 — 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. In versions 4.2.0.Final through 4.2.15.Final and 4.1.0.Final through 4.1.135.Final, a remote unauthenticated peer can leak one direct ByteBuf per HTTP/2 DATA frame in applications that enable HTTP/2 content decompression via DelegatingDecompressorFrameListener. When a DATA frame is processed for a stream whose decompressor has already been closed, Http2Decompressor.decompress(...) calls decompressor.writeInbound(data.retain()) and does not release the retained buffer on the error path, eventually exhausting direct memory and crashing the JVM. 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 21, 2026

Last Modified

July 30, 2026

Advisory Details (4)

Auto-updated Jul 22, 2026
🔬 Proof of concept available. Patch available. Sources: github_commit, github_release, github.
github Patch Available🟡 PoC Available

HTTP/2 decompression leaks ByteBuf reference count when the decompressor channel is already closed (Direct memory leak / OOM DoS) · Advisory · netty/netty · GitHub

https://github.com/netty/netty/security/advisories/GHSA-93wv-jw9v-4972
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

Vendor Advisories for CVE-2026-56819(9)

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

Patch Availability(3)

Vendor / EcosystemFixed in / PatchReleasedSource
redhatnetty-codec-http22026-09-10redhat
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-http24.1.0.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 18× in last 7d / 95× 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 173 total refreshes for this CVE.

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

Frequently asked(5)

What is CVE-2026-56819?
CVE-2026-56819 is a high vulnerability published on July 21, 2026. Netty is a network application framework for development of protocol servers and clients. In versions 4.2.0.Final through 4.2.15.Final and 4.1.0.Final through 4.1.135.Final, a remote unauthenticated peer can leak one direct ByteBuf per HTTP/2 DATA frame in applications that enable HTTP/2 content…
When was CVE-2026-56819 disclosed?
CVE-2026-56819 was first published in the National Vulnerability Database on July 21, 2026, with the most recent update on July 30, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-56819 actively exploited?
CVE-2026-56819 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 62.6% of all scored CVEs.
What is the CVSS score of CVE-2026-56819?
CVE-2026-56819 has a CVSS v3 base score of 7.5 (NVD).
How do I remediate CVE-2026-56819?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-56819, 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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