CVE-2026-42584

CRITICALNVD 9.19.1—
EchelonGraph scoreMEDIUM confidence

This critical-severity CVE scores 9.1 under NVD CVSS v3. EPSS exploit probability: 0.8%, top 47% 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
Trending — 3 sources updated this weekElevated
9.1EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 9.1Exploit: Elevated riskExposed: 0

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, HttpClientCodec pairs each inbound response with an outbound request by queue.poll() once per response, including for 1xx. If the client pipelines GET then HEAD and the server sends 103, then 200 with GET body, then 200 for HEAD, the queue pairs HEAD with the first 200. The HEAD rule then skips reading that message’s body, so the GET entity bytes stay on the stream and the following 200 is parsed from the wrong offset. This vulnerability is fixed in 4.2.13.Final and 4.1.133.Final.

CVSS v3
9.1
EG Score
9.1(medium)
EG Risk
72(Attend)
EG Risk 72/100SSVC: 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
Severity91% × 45%
Exploitation40% × 40%
Automatability100% × 15%
Action: Remediate soon — notable exploitation risk.
EPSS PROB
1%
EPSS %ILE
53%
KEV
Not listed

Published

May 13, 2026

Last Modified

August 21, 2026

Advisory Details (10)

Auto-updated Aug 1, 2026
🔬 Proof of concept available. Patch available. Sources: redhat, github.
redhat Patch Available

2477224 – (CVE-2026-42584) CVE-2026-42584 netty: io.netty/netty-codec-http: Netty: Incorrect HTTP response parsing leads to data confusion

https://bugzilla.redhat.com/show_bug.cgi?id=2477224
redhat Patch Available

cve-details

https://access.redhat.com/security/cve/CVE-2026-42584
redhat Patch Available
https://access.redhat.com/errata/RHSA-2026:42644
redhat Patch Available
https://access.redhat.com/errata/RHSA-2026:37390
redhat Patch Available
https://access.redhat.com/errata/RHSA-2026:36820
redhat Patch Available
https://access.redhat.com/errata/RHSA-2026:28010
redhat Patch Available
https://access.redhat.com/errata/RHSA-2026:25123
redhat Patch Available
https://access.redhat.com/errata/RHSA-2026:24502
redhat Patch Available
https://access.redhat.com/errata/RHSA-2026:23808
github Patch Available🟡 PoC Available

HttpClientCodec response desynchronization · Advisory · netty/netty · GitHub

https://github.com/netty/netty/security/advisories/GHSA-57rv-r2g8-2cj3

Vendor Advisories for CVE-2026-42584(10)

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

Patch Availability(8)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntulibnetty-java (1:4.0.34-1ubuntu0.1~esm4) @ xenial2026-08-23ubuntu
redhatnetty-codec-http2026-08-12redhat
redhateap7-wildfly-0:7.4.25-2.GA_redhat_00001.1.el7eap2026-08-11redhat
redhatrhoai/odh-modelmesh-rhel9:17834438162026-07-21redhat
redhatdevspaces/multicluster-redirector-rhel9:17829890272026-07-08redhat
redhatcryostat/jfr-datasource-rhel9:4.2.0-102026-06-22redhat
redhatdevspaces/server-rhel9:17806949942026-06-10redhat
redhatpatch2026-06-10redhat

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 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-http4.0.0.Alpha1 ... 4.1.99.Final (226 versions)4.1.133.Final—

Weakness Classification(1)

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

Additional Vendor Advisories

(1)

Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.

Data Freshness Timeline

(refreshed 15× in last 7d / 118× 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 233 total refreshes for this CVE.

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

Frequently asked(5)

What is CVE-2026-42584?
CVE-2026-42584 is a critical 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, HttpClientCodec pairs each inbound response with an outbound request by queue.poll() once per response, including for 1xx. If the client pipelines GET then HEAD and the server sends 103,…
When was CVE-2026-42584 disclosed?
CVE-2026-42584 was first published in the National Vulnerability Database on May 13, 2026, with the most recent update on August 21, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-42584 actively exploited?
CVE-2026-42584 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1% probability of exploitation in the next 30 days, which ranks it in the top 46.9% of all scored CVEs.
What is the CVSS score of CVE-2026-42584?
CVE-2026-42584 has a CVSS v3 base score of 9.1 (NVD).
How do I remediate CVE-2026-42584?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-42584, 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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