CVE-2021-27245
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.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (3.33%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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 3.1
- 8.1 HIGHCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 3.33% probability · 89th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-693
- Affected
- tp-link/archer a7 firmware
- Source
- zdi-disclosures@trendmicro.com
EPSS 3.3% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- https://www.zerodayinitiative.com/advisories/ZDI-21-214/Third Party Advisory, VDB Entry
- https://www.zerodayinitiative.com/advisories/ZDI-21-214/Third Party Advisory, VDB Entry
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.