CVE-2026-33871

HIGHNVD 7.57.5—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.5 under NVD CVSS v3. EPSS exploit probability: 1.1%, top 36% 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
7.5EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1.2%CVSS: 7.5Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

Netty is an asynchronous, event-driven network application framework. In versions prior to 4.1.132.Final and 4.2.10.Final, a remote user can trigger a Denial of Service (DoS) against a Netty HTTP/2 server by sending a flood of CONTINUATION frames. The server's lack of a limit on the number of CONTINUATION frames, combined with a bypass of existing size-based mitigations using zero-byte frames, allows an user to cause excessive CPU consumption with minimal bandwidth, rendering the server unresponsive. Versions 4.1.132.Final and 4.2.10.Final fix the issue.

CVSS v3
7.5
EG Score
7.5HIGHmedium confidence
EG Risk
49
EG Risk 49/100

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
Severity75% × 45%
Exploitation1% × 40%
Automatability100% × 15%
EPSS PROB
1.2%
EPSS %ILE
67th
KEV
Not listed

Published

March 27, 2026

Last Modified

September 15, 2026

Advisory Details (10)

Auto-updated Jul 3, 2026
Patch available. Sources: github, redhat.
redhat Patch Available

Affected: Red Hat Enterprise Linux 9. Red Hat Product Security has rated this update as having a security impact of Important. A Common

https://access.redhat.com/errata/RHSA-2026:18055
redhat Patch Available

Affected: Red Hat Enterprise Linux 8. Red Hat Product Security has rated this update as having a security impact of Important. A Common

https://access.redhat.com/errata/RHSA-2026:18054
redhat Patch Available
https://access.redhat.com/errata/RHSA-2026:17789
redhat Patch Available
https://access.redhat.com/errata/RHSA-2026:17668
redhat Patch Available
https://access.redhat.com/errata/RHSA-2026:14276
redhat Patch Available
https://access.redhat.com/errata/RHSA-2026:14272
redhat Patch Available
https://access.redhat.com/errata/RHSA-2026:13571
redhat Patch Available
https://access.redhat.com/errata/RHSA-2026:10184
redhat Patch Available
https://access.redhat.com/errata/RHSA-2026:10175
github Patch Available

HTTP/2 CONTINUATION Frame Flood Denial of Service · Advisory · netty/netty · GitHub

https://github.com/netty/netty/security/advisories/GHSA-w9fj-cfpg-grvv

Vendor Advisories for CVE-2026-33871(18)

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

Patch Availability(9)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
redhatrhoai/odh-trustyai-service-rhel9:17881986812026-09-08redhat
redhatnetty-codec-http22026-07-02redhat
redhatcryostat/jfr-datasource-rhel9:4.2.0-92026-05-26redhat
redhateap8-netty-transport-native-epoll-0:4.1.132-1.Final_redhat_00001.1.el8eap2026-05-18redhat
redhateap8-netty-transport-native-epoll-0:4.1.132-1.Final_redhat_00001.1.el9eap2026-05-18redhat
redhatnetty-codec-http-4.1.100.Final.jar2026-05-18redhat
redhatpatch2026-05-04redhat
redhatdevspaces/server-rhel9:17767964452026-04-23redhat
redhatrhoai/odh-modelmesh-rhel9:17767568342026-04-23redhat

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-http24.2.0.Alpha1 ... 4.2.9.Final (21 versions)
  • every version up to 4.1.132.Final: fixed in 4.1.132.Final
  • 4.2.0.Alpha1 up to 4.2.11.Final: fixed in 4.2.11.Final
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 5× in last 7d / 34× 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 141 total refreshes for this CVE.

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

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

Frequently asked(5)

What is CVE-2026-33871?
CVE-2026-33871 is a high vulnerability published on March 27, 2026. Netty is an asynchronous, event-driven network application framework. In versions prior to 4.1.132.Final and 4.2.10.Final, a remote user can trigger a Denial of Service (DoS) against a Netty HTTP/2 server by sending a flood of CONTINUATION frames. The server's lack of a limit on the number of…
When was CVE-2026-33871 disclosed?
CVE-2026-33871 was first published on March 27, 2026, with the most recent update on September 15, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-33871 actively exploited?
CVE-2026-33871 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1.2% probability of exploitation in the next 30 days (67th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-33871?
CVE-2026-33871 has a CVSS v3 base score of 7.5 (NVD).
How do I remediate CVE-2026-33871?
A fix for CVE-2026-33871 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-33871 are linked in the Vendor Advisories panel on this page.

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