CVE-2025-23018Public exploitNetwork attack vector

Traffic spoofing via unauthenticated tunnel decapsulation

Published Jan 14, 2025 · Updated Nov 3, 2025

Source verification failure in IETF IPv6 version 6 allows remote attackers to route spoofed traffic through exposed tunnel endpoints. RFC 2473 tunnel exit points decapsulate IPv4-in-IPv6 or IPv6-in-IPv6 packets without validating the outer packet's source. An exposed interface that accepts protocol 4 or 41 traffic is required, enabling one-way proxying, access-control bypass, and DDoS abuse.

CVSS severity6.5
Medium
EPSS probability1.05%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Source verification failure in IETF IPv6 version 6 allows remote attackers to route spoofed traffic through exposed tunnel endpoints. RFC 2473 tunnel exit points decapsulate IPv4-in-IPv6 or IPv6-in-IPv6 packets without validating the outer packet's source. An exposed interface that accepts protocol 4 or 41 traffic is required, enabling one-way proxying, access-control bypass, and DDoS abuse.

The record

CVE
CVE-2025-23018
Published
Jan 14, 2025
Updated
Nov 3, 2025
Vendor
Internet Engineering Task Force
Product
Internet Protocol Version 6 (IPv6)
Classifications
CWE-940, T1090.002
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 14, 2025CVE publishedPublication date reported by the CVE source.
  2. Nov 3, 2025Record 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=6

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Internet Engineering Task Force · Internet Protocol Version 6 (IPv6)version=6

Published CVSS scores

5.4MITRECVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N
6.5NIST NVDCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/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 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 exploitPublished

Weakness, pattern, technique

CWE-940Improper Verification of Source of a Communication Channel
T1090.002External Proxy

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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