CVE-2026-42577

HIGHNVD 7.57.5—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.5 under NVD CVSS v3. EPSS exploit probability: 0.4%, top 66% 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: 0%CVSS: 7.5Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

Netty is an asynchronous, event-driven network application framework. From 4.2.0.Final to 4.2.13.Final , Netty's epoll transport fails to detect and close TCP connections that receive a RST after being half-closed, leading to stale channels that are never cleaned up and, in some code paths, a 100% CPU busy-loop in the event loop thread. This vulnerability is fixed in 4.2.13.Final.

CVSS v3
7.5
EG Score
7.5(medium)
EG Risk
49(Track)
EG Risk 49/100SSVC: 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%
Exploitation0% × 40%
Automatability100% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
34%
KEV
Not listed

Published

May 13, 2026

Last Modified

May 18, 2026

Advisory Details (3)

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

Netty epoll transport denial of service via RST on half-closed TCP connection · Advisory · netty/netty · GitHub

https://github.com/netty/netty/security/advisories/GHSA-rwm7-x88c-3g2p
generic

Epoll: Correctly delete fd from epoll if there is nothing to handle by normanmaurer · Pull Request #16689 · netty/netty · GitHub

https://github.com/netty/netty/pull/16689
generic

Epoll: Correctly delete fd from epoll if there is nothing to handle (… · netty/netty@0ec3d97 · GitHub

https://github.com/netty/netty/commit/0ec3d97fab376e243d328ac95fbd288ba0f6e22d

Vendor Advisories for CVE-2026-42577(1)

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

Affected Packages

(6 across 5 ecosystems)
Maven(2)
PackageVulnerable rangeFixed inDependents
io.netty:netty-transport-classes-epoll4.2.0.Final ... 4.2.9.Final (13 versions)4.2.13.Final—
io.netty:netty-transport-native-epoll4.2.0.Final ... 4.2.9.Final (13 versions)4.2.13.Final—
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)——

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 8× in last 7d / 43× 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 131 total refreshes for this CVE.

  1. 2026-08-25 13:49 UTCEPSS rescore
  2. 2026-08-23 17:51 UTCEG score recompute
  3. 2026-08-23 00:19 UTCEPSS rescore
  4. 2026-08-22 02:08 UTCEG score recompute
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  8. 2026-08-19 17:03 UTCEPSS rescore
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  11. 2026-08-17 10:38 UTCEG score recompute
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  20. 2026-08-11 15:27 UTCEG score recompute
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  25. 2026-08-09 13:46 UTCEPSS rescore
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  1. 2026-08-09 01:54 UTCEG score recompute
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  3. 2026-08-07 19:13 UTCEG score recompute
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  5. 2026-08-06 13:46 UTCEPSS rescore
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  7. 2026-08-05 19:17 UTCEPSS rescore
  8. 2026-08-04 15:10 UTCEPSS rescore
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  22. 2026-07-25 14:18 UTCEPSS rescore
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  24. 2026-07-23 03:11 UTCEG score recompute
  25. 2026-07-22 14:08 UTCEPSS rescore
  26. 2026-07-21 15:24 UTCEPSS rescore
  27. 2026-07-20 17:08 UTCEPSS rescore
  28. 2026-07-19 02:29 UTCEPSS rescore
  29. 2026-07-18 10:04 UTCEPSS rescore
  30. 2026-07-18 02:29 UTCOSV refresh
  31. 2026-07-16 17:03 UTCEPSS rescore
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  75. 2026-06-08 14:17 UTCEPSS rescore

Frequently asked(5)

What is CVE-2026-42577?
CVE-2026-42577 is a high vulnerability published on May 13, 2026. Netty is an asynchronous, event-driven network application framework. From 4.2.0.Final to 4.2.13.Final , Netty's epoll transport fails to detect and close TCP connections that receive a RST after being half-closed, leading to stale channels that are never cleaned up and, in some code paths, a 100%…
When was CVE-2026-42577 disclosed?
CVE-2026-42577 was first published in the National Vulnerability Database on May 13, 2026, with the most recent update on May 18, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-42577 actively exploited?
CVE-2026-42577 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 66.3% of all scored CVEs.
What is the CVSS score of CVE-2026-42577?
CVE-2026-42577 has a CVSS v3 base score of 7.5 (NVD).
How do I remediate CVE-2026-42577?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-42577, 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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