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
Elevated
9.1EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.7%CVSS: 9.1Exploit: Elevated riskExposed services: Not assessed

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
9.1CRITICALmedium confidence
EG Risk
72
EG Risk 72/100

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%
EPSS PROB
0.7%
EPSS %ILE
52nd
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.
redhatMentions a patch (unverified)

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

https://access.redhat.com/errata/RHSA-2026:53644
redhatMentions a patch (unverified)
https://access.redhat.com/errata/RHSA-2026:49700
redhatMentions a patch (unverified)
https://access.redhat.com/errata/RHSA-2026:42644
redhatMentions a patch (unverified)
https://access.redhat.com/errata/RHSA-2026:37390
redhatMentions a patch (unverified)
https://access.redhat.com/errata/RHSA-2026:36820
redhatMentions a patch (unverified)
https://access.redhat.com/errata/RHSA-2026:28010
redhatMentions a patch (unverified)
https://access.redhat.com/errata/RHSA-2026:25123
redhatMentions a patch (unverified)
https://access.redhat.com/errata/RHSA-2026:24502
redhatMentions a patch (unverified)
https://access.redhat.com/errata/RHSA-2026:23808
githubMentions a patch (unverified)🟡 PoC Available

HttpClientCodec response desynchronization · Advisory · netty/netty · GitHub

https://github.com/netty/netty/security/advisories/GHSA-57rv-r2g8-2cj3
redhatMentions a patch (unverified)
https://access.redhat.com/errata/RHSA-2026:53806
redhatMentions a patch (unverified)

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
redhatMentions a patch (unverified)

cve-details

https://access.redhat.com/security/cve/CVE-2026-42584

Vendor Advisories for CVE-2026-42584(20)

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 / EcosystemFix (by version range) / 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 rangeFix by version rangeDependents
netty1:4.1.48-10 ... 1:4.1.48-9 (16 versions)
  • every version on: no fix on record
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
netty1:4.1.48-10 ... 1:4.1.48-9 (12 versions)
  • every version on: no fix on record
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
netty1:4.1.48-10 ... 1:4.1.48-16 (8 versions)
  • every version on: no fix on record
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
netty1:4.1.48-10 ... 1:4.1.48-16 (7 versions)
  • every version on: no fix on record
—
Maven(1)
PackageVulnerable rangeFix by version rangeDependents
io.netty:netty-codec-http4.0.0.Alpha1 ... 4.1.99.Final (226 versions)
  • 4.2.0.Alpha1 up to 4.2.13.Final: fixed in 4.2.13.Final
  • every version up to 4.1.133.Final: fixed in 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 8× in last 7d / 32× 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 282 total refreshes for this CVE.

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

Related CVEs(same product + same vendor + same CWE)

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 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 0.7% probability of exploitation in the next 30 days (52nd percentile of EPSS-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?
A fix for CVE-2026-42584 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-42584 are linked in the Vendor Advisories panel on this page.

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