CVE-2026-47843Network attack vector

Traffic misrouting via reused DNS resolver

Published Aug 26, 2026 · Updated Aug 26, 2026

DNS resolver reuse in Spring Reactor Netty 1.0.52 and earlier, 1.1.0 through 1.2.18, and 1.3.0 through 1.3.6 allows attackers to misroute traffic. When an application dynamically creates HttpClient or TcpClient instances with different custom resolver configurations, the library reuses a resolver configured for an earlier client; Spring has not identified the responsible class or method. Exploitation requires that multi-client configuration, and the reported consequence is traffic reaching an unintended destination rather than code execution or service interruption.

CVSS severity3.7
Low
EPSS probability0.17%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

DNS resolver reuse in Spring Reactor Netty 1.0.52 and earlier, 1.1.0 through 1.2.18, and 1.3.0 through 1.3.6 allows attackers to misroute traffic. When an application dynamically creates HttpClient or TcpClient instances with different custom resolver configurations, the library reuses a resolver configured for an earlier client; Spring has not identified the responsible class or method. Exploitation requires that multi-client configuration, and the reported consequence is traffic reaching an unintended destination rather than code execution or service interruption.

The record

CVE
CVE-2026-47843
Published
Aug 26, 2026
Updated
Aug 26, 2026
Vendor
Spring
Product
Reactor Netty
Classifications
CWE-706
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 26, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 26, 2026Record 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=0 <=1.0.52
  2. Affected versionversion=1.1.0 <=1.2.18
  3. Affected versionversion=1.3.0 <=1.3.6

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Spring · Reactor Nettyversion=0 <=1.0.52; version=1.1.0 <=1.2.18; version=1.3.0 <=1.3.6

Published CVSS scores

3.7VMware CNACVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N

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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-706Use of Incorrectly-Resolved Name or Reference

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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