CVE-2021-43783

HIGHNVD 8.58.5—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 8.5 under NVD CVSS v3. EPSS exploit probability: 1.2%, top 35% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, nvd
Trending — 3 sources updated this week
8.5
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 1%CVSS: 8.5Exploit: NoneExposed: 0

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

@backstage/plugin-scaffolder-backend is the backend for the default Backstage software templates. In affected versions a malicious actor with write access to a registered scaffolder template is able to manipulate the template in a way that writes files to arbitrary paths on the scaffolder-backend host instance. This vulnerability can in some situation also be exploited through user input when executing a template, meaning you do not need write access to the templates. This method will not allow the attacker to control the contents of the injected file however, unless the template is also crafted in a specific way that gives control of the file contents. This vulnerability is fixed in version 0.15.14 of the @backstage/plugin-scaffolder-backend. This attack is mitigated by restricting access and requiring reviews when registering or modifying scaffolder templates.

CVSS v3
8.5
EG Score
8.5(medium)
EG Risk
—
EPSS
65.1%
KEV
Not listed

Published

November 29, 2021

Last Modified

January 3, 2025

References (4)

Affected Packages

(1 across 1 ecosystem)
npm(1)
PackageVulnerable rangeFixed inDependents
@backstage/plugin-scaffolder-backend—0.15.14—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 12× in last 7d / 50× 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 105 total refreshes for this CVE.

  1. 2026-07-22 22:51 UTCEG score recompute
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Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2021-43783?
CVE-2021-43783 is a high vulnerability published on November 29, 2021. @backstage/plugin-scaffolder-backend is the backend for the default Backstage software templates. In affected versions a malicious actor with write access to a registered scaffolder template is able to manipulate the template in a way that writes files to arbitrary paths on the scaffolder-backend…
When was CVE-2021-43783 disclosed?
CVE-2021-43783 was first published in the National Vulnerability Database on November 29, 2021, with the most recent update on January 3, 2025. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-43783 actively exploited?
CVE-2021-43783 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 65.1% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2021-43783?
CVE-2021-43783 has a CVSS v3 base score of 8.5 (NVD).
How do I remediate CVE-2021-43783?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-43783, 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.

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