CVE-2021-3785: yourls is vulnerable to Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Q: How do I fix CVE-2021-3785?

yourls: upgrade to 1.8.2. Exact commands for each OS are on this page.

Q: Is CVE-2021-3785 being exploited?

CVE-2021-3785 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2021-3785 affect?

CVE-2021-3785 affects yourls. Severity is medium (CVSS 5.4). yourls is vulnerable to Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Q: How urgent is CVE-2021-3785?

Priority 37/100. Public exploit reference

Routine

MEDIUM 5.4UPGRADE

CVE-2021-3785 is a medium-severity flaw (CVSS 5.4) affecting yourls. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

yourls is vulnerable to Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Why this priority

Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score	5.4 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	Required
EPSS exploit chance	0.7% (top 46%)
CISA exploited list	No
Weakness	CWE-79
Published	2021-09-15
Last modified	2026-06-17

Publisher (CNA): huntr.dev · Vendor: yourls

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

Am I affected?

Timeline

2021-09-15 12:15 UTCPublished CVE record published
2026-06-17 04:05 UTCUpdated Record last modified

yourls yourls UPGRADE

Affected: < 1.8.2

Fixed in: 1.8.2

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy yourls || rpm -q yourls || yourls --version

2. UPGRADE to 1.8.2 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade yourls

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade yourls

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

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-2021-3785?

yourls: upgrade to 1.8.2. Exact commands for each OS are on this page.

Is CVE-2021-3785 being exploited?

CVE-2021-3785 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-2021-3785 affect?

CVE-2021-3785 affects yourls. Severity is medium (CVSS 5.4). yourls is vulnerable to Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

How urgent is CVE-2021-3785?

Priority 37/100. Public exploit reference

Related CVEs

CVE-2020-27388 MEDIUM 5.4 UPGRADE Multiple Stored Cross Site Scripting (XSS) vulnerabilities exist in the YOURLS Admin Panel, Versions 1.5 - 1.7
CVE-2022-0088 HIGH 7.4 UPGRADE Cross-Site Request Forgery (CSRF) in GitHub repository yourls/yourls prior to 1.8.3.
CVE-2021-3783 MEDIUM 6.1 UPGRADE yourls is vulnerable to Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CVE-2021-3734 HIGH 8.8 UPGRADE yourls is vulnerable to Improper Restriction of Rendered UI Layers or Frames

References

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