IPv4-in-IPv6 and IPv6-in-IPv6 tunneling (RFC 2473) do not require the validation or verification of the source of a
Source GCVE Database
Mentioned vulnerabilities
Not known to be exploited · CVSS 5.4 Medium.
Data as of 30 Oct 2026, 00:58 UTC
Thin evidence
One scorer or none| CNA (mitre) | CVSS 3.1 | 5.4 |
|---|
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:NExploitation evidence
Disclosed: evidence found.
CVE published 14 Jan 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.
What to do
AI-suggested
Mitigation should focus on validating and verifying source addresses in tunneling implementations or restricting access to exposed network interfaces where possible.
Description
IPv4-in-IPv6 and IPv6-in-IPv6 tunneling as specified in RFC 2473 lack source validation or verification, enabling attackers to spoof and route arbitrary traffic through exposed network interfaces. This vulnerability is similar to CVE-2020-10136 and can lead to partial confidentiality and integrity impacts without affecting availability.
References
- nvd.nist.gov/vuln/detail/CVE-2025-23018 (opens in a new tab)
- datatracker.ietf.org/doc/html/rfc2473 (opens in a new tab)
- papers.mathyvanhoef.com/usenix2025-tunnels.pdf (opens in a new tab)
- kb.cert.org/vuls/id/199397 (opens in a new tab)
- top10vpn.com/research/tunneling-protocol-vulnerability (opens in a new tab)