CVE-2021-31505: This vulnerability allows attackers with physical access to escalate privileges on affected installations of A

Routine

MEDIUM 6.8MITIGATE

CVE-2021-31505 is a medium-severity flaw (CVSS 6.8) affecting q plus firmware. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

This vulnerability allows attackers with physical access to escalate privileges on affected installations of Arlo Q Plus 1.9.0.3_278. Authentication is not required to exploit this vulnerability. The specific flaw exists within the SSH service. The device can be booted into a special operation mode where hard-coded credentials are accepted for SSH authentication. An attacker can leverage this vulnerability to escalate privileges and execute arbit

Why this priority

No elevated risk signals yet

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

Risk facts

CVSS score	6.8 (Medium)
Attack vector	Physical
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.6% (top 54%)
CISA exploited list	No
Weakness	CWE-798
Published	2021-06-29
Last modified	2026-06-17

Publisher (CNA): Zero Day Initiative · Vendor: arlo

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

Am I affected?

Timeline

2021-06-29 15:15 UTCPublished CVE record published
2026-06-17 03:51 UTCUpdated Record last modified

arlo q plus firmware MITIGATE

Affected: 1.9.0.3_278

Fixed in: no fixed release known

Safe to downgrade to: a release before 1.9.0.3_278

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-2021-31505?

q plus firmware: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2021-31505 being exploited?

CVE-2021-31505 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-2021-31505 affect?

CVE-2021-31505 affects q plus firmware. Severity is medium (CVSS 6.8). This vulnerability allows attackers with physical access to escalate privileges on affected installations of Arlo Q Plus 1.9.0.3_278. Authentication is not required to exploit this vulnerability. The specific flaw exists within the SSH serv

How urgent is CVE-2021-31505?

Priority 35/100. No elevated risk signals yet.

References

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