CVE-2020-23054: A cross-site scripting (XSS) vulnerability in NSK User Agent String Switcher Service v0.3.5 allows attackers t

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MEDIUM 6.1DOWNGRADE

CVE-2020-23054 is a medium-severity flaw (CVSS 6.1) affecting user-agent switcher and manager. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A cross-site scripting (XSS) vulnerability in NSK User Agent String Switcher Service v0.3.5 allows attackers to execute arbitrary web scripts or HTML via a crafted payload in the user agent input field.

Why this priority

Public exploit reference

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

Risk facts

CVSS score	6.1 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	0.7% (top 45%)
CISA exploited list	No
Weakness	CWE-79
Published	2021-10-22
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: user-agent switcher and manager project

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

Am I affected?

Timeline

2021-10-22 20:15 UTCPublished CVE record published
2026-06-17 03:04 UTCUpdated Record last modified

user-agent switcher and manager project user-agent switcher and manager DOWNGRADE

Affected: 0.3.5

Fixed in: no fixed release known

Safe to downgrade to: a release before 0.3.5

1. Check installed version

apt-cache policy user-agent-switcher-and-manager || rpm -q user-agent-switcher-and-manager || user-agent-switcher-and-manager --version

2. No fixed release: DOWNGRADE to a release before 0.3.5 (Debian / Ubuntu)

apt-cache madison user-agent-switcher-and-manager sudo apt install user-agent-switcher-and-manager=<VERSION_BEFORE_0.3.5> sudo apt-mark hold user-agent-switcher-and-manager

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list user-agent-switcher-and-manager sudo dnf downgrade user-agent-switcher-and-manager-<VERSION_BEFORE_0.3.5> sudo dnf versionlock add user-agent-switcher-and-manager

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

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-2020-23054?

user-agent switcher and manager: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2020-23054 being exploited?

CVE-2020-23054 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-2020-23054 affect?

CVE-2020-23054 affects user-agent switcher and manager. Severity is medium (CVSS 6.1). A cross-site scripting (XSS) vulnerability in NSK User Agent String Switcher Service v0.3.5 allows attackers to execute arbitrary web scripts or HTML via a crafted payload in the user agent input field.

How urgent is CVE-2020-23054?

Priority 40/100. Public exploit reference

References

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