CVE-2021-27245

HIGH
8.1
CVSS Score
Published: March 29, 2021 at 09:05 PM UTC
Updated: June 17, 2026 at 03:44 AM UTC
3 products affected across 1 vendorArcher A7 FirmwareArcher A7Link AC1750

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Severity
HIGH8.1
Exploit prediction
EPSS 3%

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < a7(us)_v5_200220v < c7(us)_v5_210125
Affected range stops below a7(us)_v5_200220, so it looks safe — our inference, not a vendor statement
Affected range stops below c7(us)_v5_210125, so it looks safe — our inference, not a vendor statement
tp-link-archer-a7 (same device)
All versions

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

References (1)

x_refsource_MISCThird Party AdvisoryVDB Entry
https://www.zerodayinitiative.com/advisories/ZDI-21-214/

CVSS

Attack Vector
NETWORK
Complexity
HIGH
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-693

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