CVE-2021-20121: The Telus Wi-Fi Hub (PRV65B444A-S-TS) with firmware version 3.00.20 is vulnerable to an authenticated arbitrar

Routine

MEDIUM 4.0MITIGATE

CVE-2021-20121 is a medium-severity flaw (CVSS 4.0) affecting prv65b444a-s-ts firmware. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

The Telus Wi-Fi Hub (PRV65B444A-S-TS) with firmware version 3.00.20 is vulnerable to an authenticated arbitrary file read. An authenticated user with physical access to the device can read arbitrary files from the device by preparing and connecting a specially prepared USB drive to the device, and making a series of crafted requests to the device's web interface.

Why this priority

Public exploit reference

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	4.0 (Medium)
Attack vector	Physical
Attack complexity	High
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.5% (top 57%)
CISA exploited list	No
Published	2021-10-11
Last modified	2026-06-17

Publisher (CNA): Tenable Network Security, Inc. · Vendor: telus

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2021-10-11 17:15 UTCPublished CVE record published
2026-06-17 03:33 UTCUpdated Record last modified

telus prv65b444a-s-ts firmware MITIGATE

Affected: 3.00.20

Fixed in: no fixed release known

Safe to downgrade to: a release before 3.00.20

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2021-20121?

prv65b444a-s-ts firmware: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2021-20121 being exploited?

CVE-2021-20121 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2021-20121 affect?

CVE-2021-20121 affects prv65b444a-s-ts firmware. Severity is medium (CVSS 4.0). The Telus Wi-Fi Hub (PRV65B444A-S-TS) with firmware version 3.00.20 is vulnerable to an authenticated arbitrary file read. An authenticated user with physical access to the device can read arbitrary files from the device by preparing and co

How urgent is CVE-2021-20121?

Priority 30/100. Public exploit reference

Software pages

Wi-Fi vulnerabilities

Related CVEs

CVE-2021-20122 HIGH 7.2 MITIGATE The Telus Wi-Fi Hub (PRV65B444A-S-TS) with firmware version 3.00.20 is affected by an authenticated command in

References

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