CVE-2021-27245

highpriority · track · 33EPSS 0.033 · 89 %ileEUUS
grimoire priorityP2 · Scheduled
Exploitable?
—
no known exploitation
Likely / severe?
3.33% (89th) EPSS
CVSS 9.3 · high
Is it mine?
3 products
Check your exposure
Who says so?
3 sources
cnnvd · enisa_euvd · nvd

EPSS · scored 2026-10-27

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.

01

cvss

Technical severity, 0–10. One row per scoring source.

9.3
010

base score 0–10 · higher = more severe · hover a vector to decode

v2.09.3highAV:N/AC:M/Au:N/C:C/I:C/A:Cprimary · NVD / NIST USexploitability 8.6 · impact 10
v3.18.1highCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:Hprimary · NVD / NIST USexploitability 2.2 · impact 5.9
v3.08.1highCVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:Hsecondary · ENISA EU
v3.08.1highCVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:Hsecondary · zdi-disclosures@trendmicro.comexploitability 2.2 · impact 5.9
v3.17.4highCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H/E:Usecondary · CVSS-BT (t0sche)
02

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-693US
03

affected products (3)

Products and version ranges known to be affected.

04

also known as (3)

Other names and identifiers for this entity.

05

sources

Which sources assert this record, and when.

cnnvdenisa_euvdnvdNVDCVE.orgMITRE
published 2021-03-29modified 2026-06-17
06

references (5)

External citations — patches, advisories, analysis.

scry

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