# CVE-2026-82509: V Programming Language net.http TLS Certificate Validation Bypass

Status: published. Published: 2026-11-10. Updated: 2026-11-14.

V programming language standard library net.http through version 0.5.2 prior to commit 4077484 contains a TLS certificate validation bypass vulnerability that allows on-path attackers to intercept HTTPS traffic by exploiting the default false value of SSLConnectConfig.validate and FetchConfig.validate, which completes TLS handshakes without verifying certificates in both the mbedtls and OpenSSL backends. Attackers can present an expired, self-signed, wrong-hostname, or untrusted-root certificate to successfully complete the handshake via http.get, http.post, or http.fetch, enabling interception or modification of HTTPS traffic unless validate: true is explicitly configured.

## Remediation

- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: CNA: VulnCheck) — https://github.com/vlang/v/commit/40774847a949722f5d090706c050b806ceeacfd1

## Affected products and versions

- vlang / v (vlang/v): ≥ 0; ≤ 0.5.2 (affected, semver); https://github.com/vlang/v/commit/40774847a949722f (unaffected, git). Source: CNA: VulnCheck

## Severity and prioritization

- CVSS 4.0: 9.1 (critical); CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N; source: CNA: VulnCheck

- CVSS 3.1: 7.4 (high); CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N; source: CNA: VulnCheck

- CVSS 4.0: 9.1 (critical); CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X; source: NVD: disclosure@vulncheck.com

- CVSS 3.1: 7.4 (high); CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N; source: NVD: disclosure@vulncheck.com

- CISA KEV: No listing in collected sources

- EPSS: 0.23% as of 2026-11-13; percentile 13.81%

- SSVC: exploitation none; automatable no; technical impact total; source ADP: CISA-ADP

- Weaknesses: CWE-295

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://github.com/vlang/v/security/advisories/GHSA-7g66-88pm-6gv6 (CNA: VulnCheck; vendor-advisory)

- https://github.com/vlang/v/commit/40774847a949722f5d090706c050b806ceeacfd1 (CNA: VulnCheck; issue-tracking, patch)

- https://www.vulncheck.com/advisories/v-programming-language-net-http-tls-certificate-validation-bypass (CNA: VulnCheck; third-party-advisory)

- https://github.com/vlang/v/commit/40774847a949722f5d090706c050b806ceeacfd1 (disclosure@vulncheck.com)

- https://github.com/vlang/v/security/advisories/GHSA-7g66-88pm-6gv6 (disclosure@vulncheck.com)

- https://www.vulncheck.com/advisories/v-programming-language-net-http-tls-certificate-validation-bypass (disclosure@vulncheck.com)

## Provenance

- CNA: VulnCheck: https://www.cve.org/CVERecord?id=CVE-2026-82509; retrieved 2026-11-14; source updated 2026-11-14

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-82509; retrieved 2026-11-13; source updated 2026-11-12

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-82509; retrieved 2026-11-14; source updated Not reported

Revision: 63cfbf018e64314259b62b0ce798eda240287f5032a41fc8ac65f337f1d60c6c

Canonical: https://y2.dev/cve/CVE-2026-82509

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