Vulnerability in Vlang V

CVE-2026-67201

V through 0.5.2, fixed in commit 85859f0, contains a server-side request forgery (SSRF) bypass vulnerability that allows attackers to circumvent host-based allowlists by exploiting a parser differential between net.urllib and net.http. Attackers can craft a URL containing a backslash in the authority section such that net.urllib.parse() extracts the trusted host for allowlist validation while net.http.get() normalizes the backslash and connects to the internal host, enabling access to internal network services that the allowlist was intended to block.

EPSS: 0.004 (32.5th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 8.6 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N.

Affected products

  • Vlang V — versions 0, 85859f0f3498d4091b38009c45ed390a97eeedc2

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-67201?
CVE-2026-67201 is a high-severity vulnerability in Vlang V, classified under CWE-436. CVSS score: 8.6/10. Published 2026-07-29.
How severe is CVE-2026-67201?
High severity. CVSS v3 base score is 8.6 out of 10.