CVE-2026-50020

MEDIUMPre-NVD 5.35.3—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 5.3 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.2%, top 86% 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, secondary
Trending — 3 sources updated this week
5.3EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 5.3Exploit: None knownExposed: 0

A fix is available — apply it.

Netty is a network application framework for development of protocol servers and clients. Prior to versions 4.1.135.Final and 4.2.15.Final, before reading the first request-line, HttpObjectDecoder skips every byte for which Character.isISOControl(b) is true (0x00–0x1F and 0x7F) as well as all whitespace. RFC 9112 §2.2 only asks servers to ignore empty CRLF lines preceding the request-line — a carefully scoped robustness allowance intended to handle HTTP/1.0 POST workarounds. Silently absorbing NUL bytes, SOH, STX, and other non-CRLF control characters goes significantly beyond this, and can be exploited for request-boundary confusion in pipelined or multiplexed transports where a front-end component treats those bytes differently. Versions 4.1.135.Final and 4.2.15.Final patch the issue.

CVSS v3
5.3
EG Score
5.3(medium)
EG Risk
28(Track)
EG Risk 28/100SSVC: 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
Severity53% × 45%
Exploitation0% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
14%
KEV
Not listed

Published

June 12, 2026

Last Modified

June 15, 2026

Advisory Details (3)

Auto-updated Jun 13, 2026
Patch available. Sources: github_release, github.
github Patch Available

HttpObjectDecoder skips arbitrary initial control characters when only initial CRLF characters are permitted · Advisory · netty/netty · GitHub

https://github.com/netty/netty/security/advisories/GHSA-hvcg-qmg6-jm4c
github_release Patch Available

netty-4.2.15.Final

Patch available: netty/netty netty-4.2.15.Final

https://github.com/netty/netty/releases/tag/netty-4.2.15.Final
github_release Patch Available

netty-4.1.135.Final

Patch available: netty/netty netty-4.1.135.Final

https://github.com/netty/netty/releases/tag/netty-4.1.135.Final

Vendor Advisories for CVE-2026-50020(3)

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

Patch Availability(1)

Vendor / EcosystemFixed in / PatchReleasedSource
redhatnetty-codec-http2026-06-17redhat

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

(1 across 1 ecosystem)
Maven(1)
PackageVulnerable rangeFixed inDependents
io.netty:netty-codec-http4.0.0.Alpha1 ... 4.1.99.Final (228 versions)4.1.135.Final—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 10× in last 7d / 60× 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.

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

Frequently asked(5)

What is CVE-2026-50020?
CVE-2026-50020 is a medium vulnerability published on June 12, 2026. Netty is a network application framework for development of protocol servers and clients. Prior to versions 4.1.135.Final and 4.2.15.Final, before reading the first request-line, HttpObjectDecoder skips every byte for which Character.isISOControl(b) is true (0x00–0x1F and 0x7F) as well as all…
When was CVE-2026-50020 disclosed?
CVE-2026-50020 was first published in the National Vulnerability Database on June 12, 2026, with the most recent update on June 15, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-50020 actively exploited?
CVE-2026-50020 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 85.8% of all scored CVEs.
What is the CVSS score of CVE-2026-50020?
CVE-2026-50020 has a CVSS v3 base score of 5.3 (NVD).
How do I remediate CVE-2026-50020?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-50020, 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.

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