CVE-2023-36673 json
An issue was discovered in Avira Phantom VPN through 2.23.1 for macOS.
published 2023-08-09 3 y ago modified 2026-06-17 4 mo ago also EUVD-2023-40616
- cvss
- 7.3
- version 3.1, NVD
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.5%
- EPSS 0.5% chance of exploitation in 30 days, percentile 45%
- public exploits
- 0
- none known
Summary
An issue was discovered in Avira Phantom VPN through 2.23.1 for macOS. The VPN client insecurely configures the operating system such that all IP traffic to the VPN server's IP address is sent in plaintext outside the VPN tunnel, even if this traffic is not generated by the VPN client, while simultaneously using plaintext DNS to look up the VPN server's IP address. This allows an adversary to trick the victim into sending traffic to arbitrary IP addresses in plaintext outside the VPN tunnel. NOTE: the tunnelcrack.mathyvanhoef.com website uses this CVE ID to refer more generally to "ServerIP attack, combined with DNS spoofing, that can leak traffic to an arbitrary IP address" rather than to only Avira Phantom VPN.
CISA SSVC
- Exploitation
- Proof of concept is public
- Automatable
- no
- Technical impact
- total
- Assessed
- 2 y ago
Exploit prediction
0.53% chance of exploitation in the next 30 days, higher than 45% of all scored CVEs (FIRST EPSS, 2026-11-08).
Exploits and checks
- tunnelcrack.mathyvanhoef.com https://tunnelcrack.mathyvanhoef.com/details.html referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| NVD | 3.1 | 7.3 | CVSS:3.1/AV:A/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N |
Classification
- Weakness
-
- CWE-319 Cleartext Transmission of Sensitive Information
References
-
tunnelcrack.mathyvanhoef.com
/details.html
exploit, third-party-advisory
-
avira.com
/en/free-vpn
product
- psirt.global.sonicwall.com /vuln-detail/SNWLID-2023-0015
Sources
- CVE List CVE-2023-36673
- NVD CVE-2023-36673
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.