CVE-2026-42584

CRITICALNVD 9.19.1
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to NVD's CVSS score.

This critical-severity CVE scores 9.1 under NVD CVSS v3. EPSS exploit probability: 0.8% (57th percentile of EPSS-scored CVEs). GitHub Security Advisory CVSS 7.3 is lower than this score; a lower GitHub score revises it only when its advisory is newer than the CVE record's last change, and this advisory (published 2026-05-07) is not newer than that change (2026-10-26), so it does not.

Triggered by: Headline CVSS from NVD CVSS v3
Sources: EPSS, GitHub Security Advisory, NVD CVSS v3
Trending — 4 sources updated this weekElevated

Also known asEUVD-2026-30127 (ENISA EUVD) · GHSA-57rv-r2g8-2cj3 (GitHub Security Advisories)Source: ENISA EUVD

9.1EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines at low or medium mission impact and sooner than that at high (the SSVC decision on this page).
  • CISA's Vulnrichment rates exploitation as PoC; EchelonGraph holds no exploit-code reference for it
CISA-KEV: Not listedEPSS PROB: 0.8%CVSS: 9.1Exploit: No code on recordExposed 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 impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.

How it’s computed (value × EchelonGraph’s weight)
Severity91% × 45%
Impact severity (EG Severity): CVSS 9.1 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation40% × 40%
EchelonGraph's fixed weight for EG-KEV Tier 3 (Elevated): a constant, not a probability.
Automatability100% × 15%
CISA's SSVC Automatable value: yes (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Attend at high (mission-essential systems).
Exploitation public PoC (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
EPSS PROB
0.8%
EPSS %ILE
57th
KEV
Not listed

What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)

The EG score (9.1): severity, escalated by confirmed exploitation. This CVE's 9.1 is its impact severity (EG Severity), not escalated.

EG Severity
9.1 CRITICALCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.NVD CVSS v3 · CVSS v3.0 or v3.1
EG Likelihood
0.8% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-11-01). FIRST's exploitation probability, not an EchelonGraph model.
Confirmed exploitation
None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
EG Priority
SSVC Track at medium mission impactTrack at low or medium mission impact; Attend at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; 60 days if it is not.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.

SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Attend at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation public PoC (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)14 days if the affected system is publicly exposed; 60 days if it is not.

The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

May 13, 2026

Last Modified

October 26, 2026

Advisory Details (13)

Auto-updated Sep 15, 2026
Patch available. Sources: github, redhat.
Red HatMentions a patch (unverified)

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

https://access.redhat.com/errata/RHSA-2026:53644
Red HatMentions a patch (unverified)
https://access.redhat.com/errata/RHSA-2026:49700
Red HatMentions a patch (unverified)
https://access.redhat.com/errata/RHSA-2026:42644
Red HatMentions a patch (unverified)
https://access.redhat.com/errata/RHSA-2026:37390
Red HatMentions a patch (unverified)
https://access.redhat.com/errata/RHSA-2026:36820
Red HatMentions a patch (unverified)
https://access.redhat.com/errata/RHSA-2026:28010
Red HatMentions a patch (unverified)
https://access.redhat.com/errata/RHSA-2026:25123
Red HatMentions a patch (unverified)
https://access.redhat.com/errata/RHSA-2026:24502
Red HatMentions a patch (unverified)
https://access.redhat.com/errata/RHSA-2026:23808
GitHub advisoryMentions a patch (unverified)

HttpClientCodec response desynchronization · Advisory · netty/netty · GitHub

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

cve-details

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

Patch Availability(19)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
ubuntulibnetty-java (1:4.1.48-16ubuntu0.1~esm2) @ resolute2026-11-02ubuntu
redhatrhoai/odh-trustyai-service-rhel9:17917925252026-10-19redhat
redhateap7-wildfly-0:7.3.19-1.GA_redhat_00004.1.el7eap2026-09-30redhat
redhateap7-wildfly-0:7.1.16-1.GA_redhat_00002.1.ep7.el72026-09-30redhat
redhatnetty-codec-http2026-09-21redhat
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
redhatio.netty/netty-codec-http:4.1.135.Final-redhat-000012026-08-03redhat
redhateap8-wildfly-0:8.1.7.1-1.GA_redhat_00004.1.el9eap2026-08-03redhat
redhatrhoai/odh-modelmesh-rhel9:17834438162026-07-21redhat
redhatdevspaces/multicluster-redirector-rhel9:17829890272026-07-08redhat
redhatpatch2026-06-25redhat
redhatcryostat/jfr-datasource-rhel9:4.2.0-102026-06-22redhat
redhatio.netty/netty-codec-http:4.1.133.Final-redhat-000022026-06-10redhat
redhatdevspaces/server-rhel9:17806949942026-06-10redhat
mavenio.netty:netty-codec-http @ 4.2.13.Final (fixes >= 4.2.0.Alpha1, <= 4.2.12.Final)—ghsa
mavenio.netty:netty-codec-http @ 4.1.133.Final (fixes <= 4.1.132.Final)—ghsa

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

(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 23× in last 7d / 82× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. 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. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

Showing the most recent 100 of 357 refreshes on record for this CVE.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. None are among the latest 100 rows. The 257 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-11-02 16:44 UTCEPSS rescoreEPSS 0.8% · 57th percentile
  2. 2026-11-02 05:46 UTCEG score recompute
  3. 2026-11-02 05:46 UTCVendor advisory
  4. 2026-11-02 05:46 UTCGHSA enrichmentGHSA-57rv-r2g8-2cj3 · GitHub severity HIGH · GitHub CVSS 7.3
  5. 2026-11-01 16:34 UTCEPSS rescoreEPSS 0.8% · 57th percentile
  6. 2026-11-01 07:50 UTCGHSA enrichmentGHSA-57rv-r2g8-2cj3 · GitHub severity HIGH · GitHub CVSS 7.3
  7. 2026-11-01 07:50 UTCEG score recompute
  8. 2026-11-01 07:30 UTCEG score recompute
  9. 2026-11-01 07:30 UTCVendor advisory
  10. 2026-10-31 16:32 UTCEPSS rescoreEPSS 0.8% · 57th percentile
  11. 2026-10-31 09:13 UTCEG score recompute
  12. 2026-10-31 09:13 UTCVendor advisory
  13. 2026-10-30 16:34 UTCEPSS rescoreEPSS 0.8% · 57th percentile
  14. 2026-10-30 10:57 UTCEG score recompute
  15. 2026-10-30 10:57 UTCVendor advisory
  16. 2026-10-29 16:33 UTCEPSS rescoreEPSS 0.8% · 57th percentile
  17. 2026-10-29 12:42 UTCEG score recompute
  18. 2026-10-29 12:42 UTCVendor advisory
  19. 2026-10-28 16:32 UTCEPSS rescoreEPSS 0.8% · 57th percentile
  20. 2026-10-28 14:25 UTCEG score recompute
  21. 2026-10-28 14:25 UTCVendor advisory
  22. 2026-10-27 16:32 UTCEPSS rescoreEPSS 0.8% · 57th percentile
  23. 2026-10-27 15:49 UTCVendor advisory
  24. 2026-10-26 17:29 UTCEG score recompute
  25. 2026-10-26 17:29 UTCVendor advisory
Show 75 more
  1. 2026-10-26 16:31 UTCEPSS rescoreEPSS 0.8% · 57th percentile
  2. 2026-10-25 20:30 UTCEG score recompute
  3. 2026-10-25 20:30 UTCVendor advisory
  4. 2026-10-25 16:33 UTCEPSS rescoreEPSS 0.8% · 57th percentile
  5. 2026-10-25 14:29 UTCEG score recompute
  6. 2026-10-24 22:14 UTCEG score recompute
  7. 2026-10-24 22:14 UTCVendor advisory
  8. 2026-10-24 16:33 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  9. 2026-10-23 23:53 UTCEG score recompute
  10. 2026-10-23 23:53 UTCVendor advisory
  11. 2026-10-23 16:31 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  12. 2026-10-23 01:31 UTCEG score recompute
  13. 2026-10-23 01:31 UTCVendor advisory
  14. 2026-10-22 16:34 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  15. 2026-10-22 02:51 UTCEG score recompute
  16. 2026-10-22 02:51 UTCVendor advisory
  17. 2026-10-21 16:33 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  18. 2026-10-21 04:28 UTCEG score recompute
  19. 2026-10-21 04:28 UTCVendor advisory
  20. 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  21. 2026-10-20 06:10 UTCEG score recompute
  22. 2026-10-20 06:10 UTCVendor advisory
  23. 2026-10-19 16:32 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  24. 2026-10-19 07:51 UTCEG score recompute
  25. 2026-10-19 07:51 UTCVendor advisory
  26. 2026-10-18 09:32 UTCVendor advisory
  27. 2026-10-18 03:40 UTCEG score recompute
  28. 2026-10-17 16:34 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  29. 2026-10-17 11:15 UTCEG score recompute
  30. 2026-10-17 11:15 UTCVendor advisory
  31. 2026-10-16 16:42 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  32. 2026-10-16 12:55 UTCEG score recompute
  33. 2026-10-16 12:55 UTCVendor advisory
  34. 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  35. 2026-10-15 14:36 UTCEG score recompute
  36. 2026-10-15 14:36 UTCVendor advisory
  37. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  38. 2026-10-14 09:11 UTCEG score recompute
  39. 2026-10-14 09:11 UTCVendor advisory
  40. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  41. 2026-10-13 06:16 UTCEG score recompute
  42. 2026-10-13 06:16 UTCVendor advisory
  43. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  44. 2026-10-12 16:07 UTCEG score recompute
  45. 2026-10-12 07:57 UTCVendor advisory
  46. 2026-10-11 19:49 UTCEG score recompute
  47. 2026-10-11 17:03 UTCEG score recompute
  48. 2026-10-11 14:29 UTCEG score recompute
  49. 2026-10-11 13:48 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  50. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  51. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  52. 2026-10-08 17:12 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  53. 2026-10-08 07:35 UTCOSV refresh
  54. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  55. 2026-10-06 15:17 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  56. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  57. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  58. 2026-10-03 14:25 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  59. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  60. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  61. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  62. 2026-09-26 15:58 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  63. 2026-09-23 17:53 UTCEPSS rescoreEPSS 0.8% · 56th percentile
  64. 2026-09-20 20:15 UTCEPSS rescoreEPSS 0.8% · 56th percentile
  65. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  66. 2026-09-18 13:23 UTCVendor advisory
  67. 2026-09-18 12:20 UTCEG score recompute
  68. 2026-09-18 12:20 UTCVendor advisory
  69. 2026-09-17 19:31 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  70. 2026-09-17 12:20 UTCVendor advisory
  71. 2026-09-17 12:11 UTCEG score recompute
  72. 2026-09-17 12:11 UTCVendor advisory
  73. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  74. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  75. 2026-09-13 16:47 UTCEPSS rescoreEPSS 0.8% · 53rd percentile

Frequently asked(5)

What is CVE-2026-42584?
CVE-2026-42584 is a critical-severity vulnerability; its CVE record was 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 the CVE record for CVE-2026-42584 published?
The CVE record for CVE-2026-42584 was published on May 13, 2026. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of October 26, 2026; the record at its source may have been updated since.
Is CVE-2026-42584 actively exploited?
CVE-2026-42584 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.8% probability of exploitation in the next 30 days (57th 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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