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.
CVE-2023-36673
Score 7.3 from GitHub Security Advisory (severity: HIGH) published 2023-08-10. NVD baseline CVSS 7.3; sources differ by 0.0.
- High severity, but no confirmed exploitation yet
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 7.3
- EG Score
- 7.3(medium)
- EG Risk
- 49(Track*)EG Risk 49/100SSVC: Track*
EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).
How it’s computedSeverity73% × 45%Exploitation40% × 40%Automatability0% × 15%Action: Watch closely — could escalate to Attend. - EPSS
- 46.2%
- KEV
- Not listed
Published
August 9, 2023
Last Modified
November 21, 2024
References (6)
- cve@mitrehttps://psirt.global.sonicwall.com/vuln-detail/SNWLID-2023-0015
- cve@mitrehttps://tunnelcrack.mathyvanhoef.com/details.html
- cve@mitrehttps://www.avira.com/en/free-vpn
- af854a3a-2127-422b-91ae-364da2661108https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2023-0015
- af854a3a-2127-422b-91ae-364da2661108https://tunnelcrack.mathyvanhoef.com/details.html
- af854a3a-2127-422b-91ae-364da2661108https://www.avira.com/en/free-vpn
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 14× in last 7d / 53× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
Showing the most recent 100 of 112 total refreshes for this CVE.
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Related CVEs(same CWE)
Same CWE
10 shownCWE-319
Frequently asked(5)
What is CVE-2023-36673?
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Dependency Blast Radius
Explore the affected products and dependency analysis for CVE-2023-36673
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