CVE-2026-33871

HIGHNVD 7.57.5
EchelonGraph scoreMEDIUM confidence

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

This high-severity CVE scores 7.5 under NVD CVSS v3. EPSS exploit probability: 1.1% (66th percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.

Triggered by: Headline CVSS from NVD CVSS v3
Sources: EPSS, NVD CVSS v3
Trending — 4 sources updated this week

Also known asEUVD-2026-16790 (ENISA EUVD) · GHSA-w9fj-cfpg-grvv (GitHub Security Advisories)Source: ENISA EUVD

7.5EG
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).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1.1%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 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)
Severity75% × 45%
Impact severity (EG Severity): CVSS 7.5 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation1.1% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
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 none (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
1.1%
EPSS %ILE
66th
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 (7.5): severity, escalated by confirmed exploitation. This CVE's 7.5 is its impact severity (EG Severity), not escalated.

EG Severity
7.5 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.NVD CVSS v3 · CVSS v3.0 or v3.1
EG Likelihood
1.1% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-31). 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 none (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

March 27, 2026

Last Modified

September 15, 2026

Advisory Details (10)

Auto-updated Jul 3, 2026
Patch available. Sources: github, redhat.
Red HatMentions a patch (unverified)

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
Red HatMentions a patch (unverified)

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
Red HatMentions a patch (unverified)
https://access.redhat.com/errata/RHSA-2026:17789
Red HatMentions a patch (unverified)
https://access.redhat.com/errata/RHSA-2026:17668
Red HatMentions a patch (unverified)
https://access.redhat.com/errata/RHSA-2026:14276
Red HatMentions a patch (unverified)
https://access.redhat.com/errata/RHSA-2026:14272
Red HatMentions a patch (unverified)
https://access.redhat.com/errata/RHSA-2026:13571
Red HatMentions a patch (unverified)
https://access.redhat.com/errata/RHSA-2026:10184
Red HatMentions a patch (unverified)
https://access.redhat.com/errata/RHSA-2026:10175
GitHub advisoryMentions a patch (unverified)

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

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

Patch Availability(14)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
redhatio.netty/netty-codec-http2:4.1.137.Final-redhat-000012026-09-22redhat
redhatrhoai/odh-trustyai-service-rhel9:17881986812026-09-08redhat
redhatnetty-codec-http22026-07-02redhat
redhatcryostat/jfr-datasource-rhel9:4.2.0-92026-05-26redhat
redhatio.netty/netty-codec-http2:4.1.132.Final-redhat-000012026-05-20redhat
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
redhatio.netty/netty-codec-http:4.1.132.Final-redhat-000012026-05-18redhat
redhatpatch2026-05-04redhat
redhatdevspaces/server-rhel9:17767964452026-04-23redhat
redhatrhoai/odh-modelmesh-rhel9:17767568342026-04-23redhat
redhatio.netty/netty-codec-http2:4.1.128.Final-redhat-000012026-04-14redhat
mavenio.netty:netty-codec-http2 @ 4.1.132.Final (fixes < 4.1.132.Final)—ghsa
mavenio.netty:netty-codec-http2 @ 4.2.11.Final (fixes >= 4.2.0.Alpha1, < 4.2.10.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-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.

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 / 45× 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 97 of 181 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. 3 repeat rows among the latest 100 are merged into the row they repeat. The 84 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 1.1% · 66th percentile
  2. 2026-11-01 16:34 UTCEPSS rescoreEPSS 1.1% · 66th percentile
  3. 2026-11-01 07:53 UTCGHSA enrichmentGHSA-w9fj-cfpg-grvv · GitHub severity HIGH
  4. 2026-11-01 07:53 UTCEG score recompute
  5. 2026-10-31 16:32 UTCEPSS rescoreEPSS 1.1% · 66th percentile
  6. 2026-10-31 15:26 UTCEG score recompute
  7. 2026-10-31 15:26 UTCVendor advisory
  8. 2026-10-30 16:34 UTCEPSS rescoreEPSS 1.1% · 66th percentile
  9. 2026-10-29 16:33 UTCEPSS rescoreEPSS 1.1% · 66th percentile
  10. 2026-10-28 16:32 UTCEPSS rescoreEPSS 1.1% · 66th percentile
  11. 2026-10-27 16:31 UTCEPSS rescoreEPSS 1.1% · 66th percentile
  12. 2026-10-26 16:31 UTCEPSS rescoreEPSS 1.1% · 66th percentile
  13. 2026-10-25 16:32 UTCEPSS rescoreEPSS 1.1% · 66th percentile
  14. 2026-10-25 14:34 UTCEG score recompute
  15. 2026-10-24 16:32 UTCEPSS rescoreEPSS 1.2% · 69th percentile
  16. 2026-10-24 15:34 UTCEG score recompute
  17. 2026-10-24 15:34 UTCVendor advisory
  18. 2026-10-23 16:31 UTCEPSS rescoreEPSS 1.2% · 67th percentile
  19. 2026-10-22 16:34 UTCEPSS rescoreEPSS 1.2% · 67th percentile
  20. 2026-10-21 16:32 UTCEPSS rescoreEPSS 1.2% · 67th percentile
  21. 2026-10-20 16:33 UTCEPSS rescoreEPSS 1.2% · 67th percentile
  22. 2026-10-19 16:31 UTCEPSS rescoreEPSS 1.2% · 67th percentile
  23. 2026-10-18 16:31 UTCEPSS rescoreEPSS 1.2% · 67th percentile
  24. 2026-10-18 03:46 UTCEG score recompute
  25. 2026-10-17 16:34 UTCEPSS rescoreEPSS 1.2% · 67th percentile
Show 72 more
  1. 2026-10-17 15:42 UTCEG score recompute
  2. 2026-10-17 15:42 UTCVendor advisory
  3. 2026-10-16 16:41 UTCEPSS rescoreEPSS 1.2% · 67th percentile
  4. 2026-10-15 16:32 UTCEPSS rescoreEPSS 1.2% · 67th percentile
  5. 2026-10-14 16:32 UTCEPSS rescoreEPSS 1.2% · 67th percentile
  6. 2026-10-13 16:34 UTCEPSS rescoreEPSS 1.2% · 67th percentile
  7. 2026-10-12 16:34 UTCEPSS rescoreEPSS 1.2% · 67th percentile
  8. 2026-10-12 16:13 UTCEG score recompute
  9. 2026-10-11 19:55 UTCEG score recompute
  10. 2026-10-11 17:08 UTCEG score recompute
  11. 2026-10-11 14:35 UTCEG score recompute
  12. 2026-10-11 13:48 UTCEPSS rescoreEPSS 1.2% · 67th percentile
  13. 2026-10-10 20:00 UTCEPSS rescoreEPSS 1.2% · 67th percentile
  14. 2026-10-09 20:07 UTCEPSS rescoreEPSS 1.2% · 67th percentile
  15. 2026-10-08 17:12 UTCEPSS rescoreEPSS 1.2% · 67th percentile
  16. 2026-10-07 23:47 UTCEPSS rescoreEPSS 1.2% · 67th percentile
  17. 2026-10-06 15:17 UTCEPSS rescoreEPSS 1.2% · 67th percentile
  18. 2026-10-05 17:42 UTCEPSS rescoreEPSS 1.2% · 67th percentile
  19. 2026-10-05 04:12 UTCOSV refresh
  20. 2026-10-04 23:22 UTCEPSS rescoreEPSS 1.2% · 67th percentile
  21. 2026-10-03 14:25 UTCEPSS rescoreEPSS 1.2% · 67th percentile
  22. 2026-10-01 19:49 UTCEPSS rescoreEPSS 1.2% · 67th percentile
  23. 2026-09-30 15:03 UTCEPSS rescoreEPSS 1.2% · 67th percentile
  24. 2026-09-28 13:51 UTCEPSS rescoreEPSS 1.2% · 66th percentile
  25. 2026-09-27 13:48 UTCEPSS rescoreEPSS 1.2% · 66th percentile
  26. 2026-09-26 15:58 UTCEPSS rescoreEPSS 1.2% · 66th percentile
  27. 2026-09-26 00:26 UTCEPSS rescoreEPSS 1.2% · 66th percentile
  28. 2026-09-18 19:28 UTCEPSS rescoreEPSS 1.1% · 64th percentile
  29. 2026-09-17 19:30 UTCEPSS rescoreEPSS 1.1% · 64th percentile
  30. 2026-09-16 14:08 UTCEPSS rescoreEPSS 1.1% · 64th percentile
  31. 2026-09-16 05:15 UTCEPSS rescoreEPSS 1.1% · 64th percentile
  32. 2026-09-15 12:14 UTCEG score recompute
  33. 2026-09-15 12:14 UTCVendor advisory
  34. 2026-09-15 03:11 UTCEPSS rescoreEPSS 1.1% · 64th percentile
  35. 2026-09-14 13:39 UTCVendor advisory
  36. 2026-09-14 12:35 UTCEG score recompute
  37. 2026-09-14 12:35 UTCVendor advisory
  38. 2026-09-13 16:47 UTCEPSS rescoreEPSS 1.1% · 64th percentile
  39. 2026-09-12 15:01 UTCEPSS rescoreEPSS 1.1% · 64th percentile
  40. 2026-09-11 14:53 UTCEPSS rescoreEPSS 1.1% · 64th percentile
  41. 2026-09-11 13:25 UTCVendor advisory
  42. 2026-09-11 12:25 UTCEG score recompute
  43. 2026-09-11 12:25 UTCVendor advisory
  44. 2026-09-11 09:37 UTCEPSS rescoreEPSS 1.1% · 64th percentile
  45. 2026-09-10 09:34 UTCEPSS rescoreEPSS 1.1% · 64th percentile
  46. 2026-09-09 13:42 UTCVendor advisory
  47. 2026-09-09 12:40 UTCEG score recompute
  48. 2026-09-09 12:40 UTCVendor advisory
  49. 2026-09-08 22:00 UTCEPSS rescoreEPSS 1.1% · 64th percentile
  50. 2026-09-07 16:01 UTCEPSS rescoreEPSS 1.1% · 64th percentile
  51. 2026-09-06 13:47 UTCEPSS rescoreEPSS 1.1% · 64th percentile
  52. 2026-09-05 01:44 UTCOSV refresh
  53. 2026-09-04 05:06 UTCEPSS rescoreEPSS 1.1% · 64th percentile
  54. 2026-09-02 14:12 UTCEPSS rescoreEPSS 1.1% · 64th percentile
  55. 2026-09-01 13:53 UTCEPSS rescoreEPSS 1.1% · 64th percentile
  56. 2026-09-01 04:39 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
  57. 2026-08-30 19:17 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
  58. 2026-08-30 01:22 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
  59. 2026-08-28 21:41 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
  60. 2026-08-27 14:25 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
  61. 2026-08-26 14:46 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
  62. 2026-08-25 13:49 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
  63. 2026-08-24 14:17 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
  64. 2026-08-21 23:49 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
  65. 2026-08-20 22:55 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
  66. 2026-08-19 17:03 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
  67. 2026-08-18 13:48 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
  68. 2026-08-18 12:21 UTCVendor advisory
  69. 2026-08-17 12:13 UTCEG score recompute
  70. 2026-08-17 12:13 UTCVendor advisory
  71. 2026-08-16 14:56 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
  72. 2026-08-16 09:57 UTCEG score recompute

Frequently asked(5)

What is CVE-2026-33871?
CVE-2026-33871 is a high-severity vulnerability; its CVE record was 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 the CVE record for CVE-2026-33871 published?
The CVE record for CVE-2026-33871 was published on March 27, 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 September 15, 2026; the record at its source may have been updated since.
Is CVE-2026-33871 actively exploited?
CVE-2026-33871 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1.1% probability of exploitation in the next 30 days (66th 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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