{"cve":"CVE-2021-27245","nvd":{"published":"2021-03-29T21:15:12.953","modified":"2026-06-17T03:44:32.293","status":"Modified","description":"This vulnerability allows a firewall bypass on affected installations of TP-Link Archer A7 prior to Archer C7(US)_V5_210125 and Archer A7(US)_V5_200220 AC1750 routers. Authentication is not required to exploit this vulnerability. The specific flaw exists within the handling of IPv6 connections. The issue results from the lack of proper filtering of IPv6 SSH connections. An attacker can leverage this in conjunction with other vulnerabilities to execute code in the context of root. Was ZDI-CAN-12309.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H","score":8.1},"cwes":["CWE-693"],"references":["https://www.zerodayinitiative.com/advisories/ZDI-21-214/","https://www.zerodayinitiative.com/advisories/ZDI-21-214/"],"products":["tp-link:archer_a7_firmware"],"source":"nvd","synced_at":"2026-10-19T21:17:01.373894544+00:00"},"epss":{"cve":"CVE-2021-27245","score":0.03329,"percentile":0.88618,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}