CVE-2026-42578

HIGHNVD 7.57.5—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.5 under NVD CVSS v3. EPSS exploit probability: 1.1%, top 38% 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
7.5EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 7.5Exploit: 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, Netty's HttpProxyHandler constructs HTTP CONNECT requests with header validation explicitly disabled. The newInitialMessage() method creates headers using DefaultHttpHeadersFactory.headersFactory().withValidation(false), then adds user-provided outboundHeaders without any CRLF validation. This allows an attacker who can influence the outbound headers to inject arbitrary HTTP headers into the CONNECT request sent to the proxy server. This vulnerability is fixed in 4.2.13.Final and 4.1.133.Final.

CVSS v3
7.5
EG Score
7.5(medium)
EG Risk
50(Track)
EG Risk 50/100SSVC: Track

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%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
1%
EPSS %ILE
62%
KEV
Not listed

Published

May 13, 2026

Last Modified

August 13, 2026

Advisory Details (1)

Auto-updated May 18, 2026
🔬 Proof of concept available. Patch available. Sources: github.
github Patch Available🟡 PoC Available

HTTP Header Injection via HttpProxyHandler Disabled Validation in Netty · Advisory · netty/netty · GitHub

https://github.com/netty/netty/security/advisories/GHSA-45q3-82m4-75jr

Vendor Advisories for CVE-2026-42578(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-handler-proxy2026-08-12redhat
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
redhatpatch2026-06-10redhat
redhatdevspaces/server-rhel9:17806949942026-06-10redhat

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-handler-proxy4.2.0.Alpha1 ... 4.2.9.Final (23 versions)4.2.13.Final—

Weakness Classification(2)

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 11× in last 7d / 74× 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 179 total refreshes for this CVE.

  1. 2026-08-25 13:49 UTCEPSS rescore
  2. 2026-08-23 17:50 UTCEG score recompute
  3. 2026-08-23 17:50 UTCVendor advisory
  4. 2026-08-23 00:19 UTCEPSS rescore
  5. 2026-08-22 02:08 UTCEG score recompute
  6. 2026-08-22 02:08 UTCVendor advisory
  7. 2026-08-21 23:49 UTCEPSS rescore
  8. 2026-08-20 22:55 UTCEPSS rescore
  9. 2026-08-20 19:48 UTCEG score recompute
  10. 2026-08-20 19:48 UTCVendor advisory
  11. 2026-08-19 17:03 UTCEPSS rescore
  12. 2026-08-18 13:48 UTCEPSS rescore
  13. 2026-08-17 13:47 UTCEPSS rescore
  14. 2026-08-17 10:38 UTCEG score recompute
  15. 2026-08-17 10:38 UTCVendor advisory
  16. 2026-08-16 14:56 UTCEPSS rescore
  17. 2026-08-16 04:02 UTCEG score recompute
  18. 2026-08-16 04:02 UTCVendor advisory
  19. 2026-08-16 02:14 UTCEPSS rescore
  20. 2026-08-15 01:44 UTCEG score recompute
  21. 2026-08-15 01:44 UTCVendor advisory
  22. 2026-08-15 01:30 UTCEPSS rescore
  23. 2026-08-14 14:07 UTCVendor advisory
  24. 2026-08-14 02:31 UTCEG score recompute
  25. 2026-08-14 02:31 UTCVendor advisory
Show 75 more
  1. 2026-08-13 22:00 UTCEPSS rescore
  2. 2026-08-13 13:37 UTCVendor advisory
  3. 2026-08-13 12:28 UTCVendor advisory
  4. 2026-08-13 00:14 UTCEG score recompute
  5. 2026-08-13 00:14 UTCVendor advisory
  6. 2026-08-12 13:51 UTCEPSS rescore
  7. 2026-08-12 12:37 UTCVendor advisory
  8. 2026-08-12 12:12 UTCVendor advisory
  9. 2026-08-11 15:27 UTCEG score recompute
  10. 2026-08-11 15:27 UTCVendor advisory
  11. 2026-08-11 13:43 UTCEPSS rescore
  12. 2026-08-11 00:56 UTCEG score recompute
  13. 2026-08-11 00:56 UTCVendor advisory
  14. 2026-08-11 00:00 UTCEPSS rescore
  15. 2026-08-10 12:44 UTCVendor advisory
  16. 2026-08-10 01:07 UTCEG score recompute
  17. 2026-08-10 01:07 UTCVendor advisory
  18. 2026-08-09 13:46 UTCEPSS rescore
  19. 2026-08-09 13:30 UTCVendor advisory
  20. 2026-08-09 01:54 UTCEG score recompute
  21. 2026-08-09 01:54 UTCVendor advisory
  22. 2026-08-08 16:37 UTCEPSS rescore
  23. 2026-08-08 07:48 UTCVendor advisory
  24. 2026-08-07 20:12 UTCEG score recompute
  25. 2026-08-07 20:12 UTCVendor advisory
  26. 2026-08-07 08:35 UTCVendor advisory
  27. 2026-08-06 20:54 UTCEG score recompute
  28. 2026-08-06 20:54 UTCVendor advisory
  29. 2026-08-06 13:46 UTCEPSS rescore
  30. 2026-08-06 09:18 UTCVendor advisory
  31. 2026-08-05 21:40 UTCEG score recompute
  32. 2026-08-05 21:40 UTCVendor advisory
  33. 2026-08-05 19:17 UTCEPSS rescore
  34. 2026-08-04 15:10 UTCEPSS rescore
  35. 2026-08-04 10:38 UTCEPSS rescore
  36. 2026-08-03 19:08 UTCEG score recompute
  37. 2026-08-03 19:08 UTCVendor advisory
  38. 2026-08-03 10:36 UTCEPSS rescore
  39. 2026-08-02 19:45 UTCVendor advisory
  40. 2026-08-02 08:08 UTCEG score recompute
  41. 2026-08-02 08:08 UTCVendor advisory
  42. 2026-08-02 02:27 UTCEPSS rescore
  43. 2026-08-01 19:46 UTCEG score recompute
  44. 2026-08-01 19:46 UTCVendor advisory
  45. 2026-08-01 04:16 UTCEPSS rescore
  46. 2026-07-30 16:28 UTCEPSS rescore
  47. 2026-07-30 01:30 UTCEPSS rescore
  48. 2026-07-28 15:36 UTCEPSS rescore
  49. 2026-07-27 14:13 UTCEPSS rescore
  50. 2026-07-26 14:54 UTCEPSS rescore
  51. 2026-07-26 14:54 UTCEPSS rescore
  52. 2026-07-25 14:18 UTCEPSS rescore
  53. 2026-07-24 14:17 UTCEPSS rescore
  54. 2026-07-23 14:18 UTCEPSS rescore
  55. 2026-07-23 03:11 UTCEG score recompute▲ 4.60
  56. 2026-07-22 14:08 UTCEPSS rescore
  57. 2026-07-21 15:24 UTCEPSS rescore
  58. 2026-07-20 17:08 UTCEPSS rescore
  59. 2026-07-19 14:31 UTCEPSS rescore
  60. 2026-07-19 02:29 UTCEPSS rescore
  61. 2026-07-18 10:04 UTCEPSS rescore
  62. 2026-07-16 17:03 UTCEPSS rescore
  63. 2026-07-15 16:57 UTCEPSS rescore
  64. 2026-07-15 07:49 UTCOSV refresh
  65. 2026-07-15 02:00 UTCEPSS rescore
  66. 2026-07-13 22:30 UTCEPSS rescore
  67. 2026-07-13 06:13 UTCEPSS rescore
  68. 2026-07-12 05:46 UTCEPSS rescore
  69. 2026-07-11 08:27 UTCEPSS rescore
  70. 2026-07-09 19:10 UTCEPSS rescore
  71. 2026-07-08 15:15 UTCEPSS rescore
  72. 2026-07-07 13:46 UTCEPSS rescore
  73. 2026-07-06 16:27 UTCEPSS rescore
  74. 2026-07-06 16:27 UTCEPSS rescore
  75. 2026-07-06 02:23 UTCEPSS rescore

Frequently asked(5)

What is CVE-2026-42578?
CVE-2026-42578 is a high 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, Netty's HttpProxyHandler constructs HTTP CONNECT requests with header validation explicitly disabled. The newInitialMessage() method creates headers using…
When was CVE-2026-42578 disclosed?
CVE-2026-42578 was first published in the National Vulnerability Database on May 13, 2026, with the most recent update on August 13, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-42578 actively exploited?
CVE-2026-42578 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 37.9% of all scored CVEs.
What is the CVSS score of CVE-2026-42578?
CVE-2026-42578 has a CVSS v3 base score of 7.5 (NVD).
How do I remediate CVE-2026-42578?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-42578, 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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