CVE-2023-34054Network attack vector

Denial of service via unbounded metrics tags

Published Nov 28, 2023 · Updated Aug 2, 2024

Resource exhaustion in Reactor Netty HTTP Server 1.0.0 through 1.0.38 and 1.1.0 through 1.1.12 allows remote attackers to interrupt service. The built-in Micrometer recorder uses request-derived HTTP values as metric tag values without bounding cardinality, so distinct values retain increasing meter state. The behavior is reachable only when built-in Micrometer metrics are enabled; sustained crafted requests consume memory and interrupt the hosting application.

CVSS severity5.3
Medium
EPSS probability0.91%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Resource exhaustion in Reactor Netty HTTP Server 1.0.0 through 1.0.38 and 1.1.0 through 1.1.12 allows remote attackers to interrupt service. The built-in Micrometer recorder uses request-derived HTTP values as metric tag values without bounding cardinality, so distinct values retain increasing meter state. The behavior is reachable only when built-in Micrometer metrics are enabled; sustained crafted requests consume memory and interrupt the hosting application.

The record

CVE
CVE-2023-34054
Published
Nov 28, 2023
Updated
Aug 2, 2024
Vendor
Spring
Product
Reactor Netty
Classifications
T1499.003
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 28, 2023CVE publishedPublication date reported by the CVE source.
  2. Aug 2, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=1.0.0 <1.0.39
  2. Affected versionversion=1.1.0 <1.1.13
  3. Affected versionversion=older unsupported versions

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Spring · Reactor Nettyversion=1.0.0 <1.0.39; version=1.1.0 <1.1.13; version=older unsupported versions

Published CVSS scores

7.5GitHubCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
5.3SpringCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499.003Application Exhaustion Flood

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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