What’s Vulnerable › Vulnerabilities

CVE-2021-4070: Off-by-one Error in v2fly/v2ray-core

• Severity: critical (CVSS 9.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.9% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2022-02-23 · updated 2026-06-17
• Weakness: CWE-193

Description

Off-by-one Error in GitHub repository v2fly/v2ray-core prior to 4.44.0.

Affected products

• v2fly/v2ray-core: before 4.44.0 — fixed in 4.44.0

How to fix

Upgrade to a fixed version: v2fly/v2ray-core 4.44.0. Check the vendor advisory for mitigations.

References

• https://github.com/v2fly/v2ray-core/commit/c1af2bfd7aa59a4482aa7f6ec4b9208c1d350b5c
• https://huntr.dev/bounties/8da19456-4d89-41ef-9781-a41efd6a1877
• https://github.com/v2fly/v2ray-core/commit/c1af2bfd7aa59a4482aa7f6ec4b9208c1d350b5c
• https://huntr.dev/bounties/8da19456-4d89-41ef-9781-a41efd6a1877

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