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
5.3EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.4%CVSS: 5.3Exploit: None knownExposed services: Not assessed

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
5.3MEDIUMmedium confidence
EG Risk
28
EG Risk 28/100

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
Severity53% × 45%
Exploitation0% × 40%
Automatability30% × 15%
EPSS PROB
0.4%
EPSS %ILE
31st
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(4)

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

Patch Availability(2)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
redhatpatch2026-08-04redhat
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

(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 (228 versions)
  • 4.2.0.Final up to 4.2.15.Final: fixed in 4.2.15.Final
  • every version up to 4.1.135.Final: fixed in 4.1.135.Final
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 7× in last 7d / 23× 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 202 total refreshes for this CVE.

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

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

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 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 0.4% probability of exploitation in the next 30 days (31st percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-50020?
CVE-2026-50020 has a CVSS base score of 5.3 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-50020?
A fix for CVE-2026-50020 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-50020 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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