CVE-2021-3783

MEDIUMNVD 6.16.6▲
EchelonGraph scoreMEDIUM confidence

Score 6.6 from GitHub Security Advisory published 2021-09-20. NVD baseline CVSS 6.1; sources differ by 0.5.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
Trending — 3 sources updated this week
6.1
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 1%CVSS: 6.1Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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

CVSS v3
6.1
EG Score
6.6(medium)
EG Risk
34(Track)
EG Risk 34/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity66% × 45%
Exploitation1% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS
49.2%
KEV
Not listed

Published

September 15, 2021

Last Modified

November 21, 2024

References (4)

Patch Availability(1)

Vendor / EcosystemFixed in / PatchReleasedSource
composeryourls/yourls—ghsa

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(1 across 1 ecosystem)
Packagist(1)
PackageVulnerable rangeFixed inDependents
yourls/yourls1.7.1 ... 1.8.2 (10 versions)——

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 13× in last 7d / 51× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 108 total refreshes for this CVE.

  1. 2026-07-23 02:03 UTCEG score recompute
  2. 2026-07-22 22:49 UTCEG score recompute
  3. 2026-07-22 14:06 UTCEPSS rescore
  4. 2026-07-21 15:22 UTCEPSS rescore
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  9. 2026-07-18 11:59 UTCOSV refresh
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  1. 2026-07-07 13:43 UTCEPSS rescore
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  45. 2026-06-12 23:10 UTCEPSS rescore
  46. 2026-06-12 21:40 UTCOSV refresh
  47. 2026-06-11 13:58 UTCEPSS rescore
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  49. 2026-06-10 22:16 UTCEPSS rescore
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Related CVEs(same product + same CWE)

Same product

2 shown

composer:yourls/yourls

Frequently asked(5)

What is CVE-2021-3783?
CVE-2021-3783 is a medium vulnerability published on September 15, 2021. yourls is vulnerable to Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
When was CVE-2021-3783 disclosed?
CVE-2021-3783 was first published in the National Vulnerability Database on September 15, 2021, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-3783 actively exploited?
CVE-2021-3783 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 49.2% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2021-3783?
CVE-2021-3783 has a CVSS v3 base score of 6.1 (NVD). EchelonGraph synthesises NVD + CISA KEV + FIRST EPSS + GHSA into a combined EG score of 6.6.
How do I remediate CVE-2021-3783?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-3783, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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