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 46% 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
54%
KEV
Not listed

Published

May 13, 2026

Last Modified

September 18, 2026

Advisory Details (13)

Auto-updated Sep 15, 2026
🔬 Proof of concept available. Patch available. Sources: github, redhat.
redhat Patch Available

Affected: Red Hat Enterprise Linux 7. Red Hat Product Security has rated

https://access.redhat.com/errata/RHSA-2026:53644
redhat Patch Available
https://access.redhat.com/errata/RHSA-2026:49700
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
redhat Patch Available
https://access.redhat.com/errata/RHSA-2026:53806
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

Vendor Advisories for CVE-2026-42584(15)

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

Patch Availability(13)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntulibnetty-java (1:4.1.48-16ubuntu0.1~esm2) @ resolute2026-09-18ubuntu
redhatnetty-codec-http2026-09-10redhat
redhatrhoai/odh-trustyai-service-rhel9:17881986812026-09-08redhat
redhateap7-wildfly-0:7.4.25-2.GA_redhat_00001.1.el8eap2026-08-11redhat
redhateap7-wildfly-0:7.4.25-2.GA_redhat_00001.1.el7eap2026-08-11redhat
redhateap7-wildfly-0:7.4.25-2.GA_redhat_00001.1.el9eap2026-08-11redhat
redhateap8-wildfly-0:8.1.7.1-1.GA_redhat_00004.1.el9eap2026-08-03redhat
redhatio.netty/netty-codec-http:4.1.135.Final-redhat-000012026-08-03redhat
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

(3)

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 12× in last 7d / 49× 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 268 total refreshes for this CVE.

  1. 2026-09-18 19:28 UTCEPSS rescore
  2. 2026-09-18 13:23 UTCVendor advisory
  3. 2026-09-18 12:20 UTCEG score recompute
  4. 2026-09-18 12:20 UTCVendor advisory
  5. 2026-09-17 19:31 UTCEPSS rescore
  6. 2026-09-17 12:20 UTCVendor advisory
  7. 2026-09-17 12:11 UTCEG score recompute
  8. 2026-09-17 12:11 UTCVendor advisory
  9. 2026-09-16 14:08 UTCEPSS rescore
  10. 2026-09-16 05:15 UTCEPSS rescore
  11. 2026-09-13 16:47 UTCEPSS rescore
  12. 2026-09-12 15:01 UTCEPSS rescore
  13. 2026-09-11 14:53 UTCEPSS rescore
  14. 2026-09-11 13:25 UTCVendor advisory
  15. 2026-09-11 12:21 UTCEG score recompute
  16. 2026-09-11 12:21 UTCVendor advisory
  17. 2026-09-11 09:37 UTCEPSS rescore
  18. 2026-09-10 09:34 UTCEPSS rescore
  19. 2026-09-09 13:41 UTCVendor advisory
  20. 2026-09-09 12:39 UTCEG score recompute
  21. 2026-09-09 12:39 UTCVendor advisory
  22. 2026-09-08 22:00 UTCEPSS rescore
  23. 2026-09-07 16:01 UTCEPSS rescore
  24. 2026-09-07 13:54 UTCVendor advisory
  25. 2026-09-07 12:42 UTCEG score recompute
Show 75 more
  1. 2026-09-07 12:42 UTCVendor advisory
  2. 2026-09-06 13:47 UTCEPSS rescore
  3. 2026-09-04 05:06 UTCEPSS rescore
  4. 2026-09-02 14:12 UTCEPSS rescore
  5. 2026-09-01 13:54 UTCEPSS rescore
  6. 2026-08-30 19:17 UTCEPSS rescore
  7. 2026-08-30 01:22 UTCEPSS rescore
  8. 2026-08-28 21:41 UTCEPSS rescore
  9. 2026-08-27 14:25 UTCEPSS rescore
  10. 2026-08-26 14:46 UTCEPSS rescore
  11. 2026-08-25 13:49 UTCEPSS rescore
  12. 2026-08-23 21:34 UTCVendor advisory
  13. 2026-08-23 17:50 UTCEG score recompute
  14. 2026-08-23 17:50 UTCVendor advisory
  15. 2026-08-23 00:19 UTCEPSS rescore
  16. 2026-08-22 02:05 UTCEG score recompute
  17. 2026-08-22 02:05 UTCVendor advisory
  18. 2026-08-21 23:49 UTCEPSS rescore
  19. 2026-08-21 13:19 UTCVendor advisory
  20. 2026-08-21 12:31 UTCEG score recompute
  21. 2026-08-21 12:31 UTCVendor advisory
  22. 2026-08-20 22:55 UTCEPSS rescore
  23. 2026-08-20 19:47 UTCEG score recompute
  24. 2026-08-20 19:47 UTCVendor advisory
  25. 2026-08-19 17:03 UTCEPSS rescore
  26. 2026-08-18 13:48 UTCEPSS rescore
  27. 2026-08-17 14:41 UTCEG score recompute
  28. 2026-08-17 14:41 UTCVendor advisory
  29. 2026-08-17 13:47 UTCEPSS rescore
  30. 2026-08-17 10:32 UTCEG score recompute
  31. 2026-08-17 10:32 UTCVendor advisory
  32. 2026-08-16 14:56 UTCEPSS rescore
  33. 2026-08-16 11:33 UTCVendor advisory
  34. 2026-08-16 07:49 UTCVendor advisory
  35. 2026-08-16 04:02 UTCEG score recompute
  36. 2026-08-16 04:02 UTCVendor advisory
  37. 2026-08-16 02:14 UTCEPSS rescore
  38. 2026-08-15 01:30 UTCEPSS rescore
  39. 2026-08-15 01:28 UTCVendor advisory
  40. 2026-08-14 21:45 UTCVendor advisory
  41. 2026-08-14 18:01 UTCVendor advisory
  42. 2026-08-14 13:42 UTCVendor advisory
  43. 2026-08-14 09:58 UTCVendor advisory
  44. 2026-08-14 06:14 UTCVendor advisory
  45. 2026-08-14 02:30 UTCEG score recompute
  46. 2026-08-14 02:30 UTCVendor advisory
  47. 2026-08-13 22:00 UTCEPSS rescore
  48. 2026-08-13 13:37 UTCVendor advisory
  49. 2026-08-13 12:28 UTCVendor advisory
  50. 2026-08-13 08:15 UTCVendor advisory
  51. 2026-08-13 03:35 UTCVendor advisory
  52. 2026-08-12 23:51 UTCVendor advisory
  53. 2026-08-12 20:07 UTCVendor advisory
  54. 2026-08-12 16:23 UTCEG score recompute
  55. 2026-08-12 16:23 UTCVendor advisory
  56. 2026-08-12 13:51 UTCEPSS rescore
  57. 2026-08-12 12:37 UTCVendor advisory
  58. 2026-08-12 12:12 UTCVendor advisory
  59. 2026-08-11 22:57 UTCVendor advisory
  60. 2026-08-11 19:14 UTCVendor advisory
  61. 2026-08-11 15:27 UTCEG score recompute
  62. 2026-08-11 15:27 UTCVendor advisory
  63. 2026-08-11 13:43 UTCEPSS rescore
  64. 2026-08-11 08:24 UTCVendor advisory
  65. 2026-08-11 04:39 UTCVendor advisory
  66. 2026-08-11 00:56 UTCEG score recompute
  67. 2026-08-11 00:56 UTCVendor advisory
  68. 2026-08-11 00:00 UTCEPSS rescore
  69. 2026-08-10 11:56 UTCVendor advisory
  70. 2026-08-10 08:12 UTCVendor advisory
  71. 2026-08-10 04:28 UTCVendor advisory
  72. 2026-08-10 00:44 UTCVendor advisory
  73. 2026-08-09 21:00 UTCVendor advisory
  74. 2026-08-09 17:16 UTCEG score recompute
  75. 2026-08-09 17:16 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 September 18, 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 45.7% 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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