CVE-2023-34462

MEDIUMNVD 6.56.5—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 6.5 under NVD CVSS v3. EPSS exploit probability: 2.5%, top 17% 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
6.5EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 2%CVSS: 6.5Exploit: None knownExposed: 0

A fix is available — apply it.

Netty is an asynchronous event-driven network application framework for rapid development of maintainable high performance protocol servers & clients. The SniHandler can allocate up to 16MB of heap for each channel during the TLS handshake. When the handler or the channel does not have an idle timeout, it can be used to make a TCP server using the SniHandler to allocate 16MB of heap. The SniHandler class is a handler that waits for the TLS handshake to configure a SslHandler according to the indicated server name by the ClientHello record. For this matter it allocates a ByteBuf using the value defined in the ClientHello record. Normally the value of the packet should be smaller than the handshake packet but there are not checks done here and the way the code is written, it is possible to craft a packet that makes the SslClientHelloHandler. This vulnerability has been fixed in version 4.1.94.Final.

CVSS v3
6.5
EG Score
6.5(medium)
EG Risk
30(Track)
EG Risk 30/100SSVC: 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
Severity65% × 45%
Exploitation2% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
2%
EPSS %ILE
83%
KEV
Not listed

Published

June 22, 2023

Last Modified

November 21, 2024

References (10)

Vendor Advisories for CVE-2023-34462(12)

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

Patch Availability(8)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntulibnetty-java (1:4.1.48-4+deb11u2build0.22.04.1) @ jammy2026-05-24ubuntu
redhatnetty2024-01-10redhat
redhatio.netty/netty-handler:4.1.100.Final-redhat-000012023-12-07redhat
redhatcryostat-tech-preview/jfr-datasource-rhel8:2.4.0-22023-12-06redhat
redhateap7-netty-transport-native-epoll-0:4.1.94-1.Final_redhat_00001.1.el8eap2023-10-06redhat
redhateap7-netty-transport-native-epoll-0:4.1.94-1.Final_redhat_00001.1.el9eap2023-10-06redhat
redhateap7-netty-transport-native-epoll-0:4.1.94-1.Final_redhat_00001.1.el7eap2023-10-05redhat
redhatpatch2023-09-14redhat

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 rangeFixed inDependents
netty1:4.1.48-4, 1:4.1.48-4+deb11u11:4.1.48-4+deb11u2—
Debian:12(1)
PackageVulnerable rangeFixed inDependents
netty1:4.1.48-71:4.1.48-7+deb12u1—
Debian:13(1)
PackageVulnerable rangeFixed inDependents
netty—1:4.1.48-8—
Debian:14(1)
PackageVulnerable rangeFixed inDependents
netty—1:4.1.48-8—
Maven(1)
PackageVulnerable rangeFixed inDependents
io.netty:netty-handler4.0.0.Alpha1 ... 4.1.93.Final (187 versions)4.1.94.Final—

Weakness Classification(2)

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

Additional Vendor Advisories

(2)

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 6× in last 7d / 33× 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 149 total refreshes for this CVE.

  1. 2026-08-25 13:46 UTCEPSS rescore
  2. 2026-08-24 14:14 UTCEPSS rescore
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  8. 2026-08-17 14:59 UTCOSV refresh
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  25. 2026-08-02 09:29 UTCOSV refresh
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  26. 2026-07-16 17:01 UTCEPSS rescore
  27. 2026-07-15 17:19 UTCOSV refresh
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  50. 2026-06-30 23:21 UTCEPSS rescore
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  58. 2026-06-27 17:34 UTCOSV refresh
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Frequently asked(5)

What is CVE-2023-34462?
CVE-2023-34462 is a medium vulnerability published on June 22, 2023. Netty is an asynchronous event-driven network application framework for rapid development of maintainable high performance protocol servers & clients. The SniHandler can allocate up to 16MB of heap for each channel during the TLS handshake. When the handler or the channel does not have an idle…
When was CVE-2023-34462 disclosed?
CVE-2023-34462 was first published in the National Vulnerability Database on June 22, 2023, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2023-34462 actively exploited?
CVE-2023-34462 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 2% probability of exploitation in the next 30 days, which ranks it in the top 16.8% of all scored CVEs.
What is the CVSS score of CVE-2023-34462?
CVE-2023-34462 has a CVSS v3 base score of 6.5 (NVD).
How do I remediate CVE-2023-34462?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2023-34462, 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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