What is CVE-2026-29186?

CVE-2026-29186 is a high-severity vulnerability in Backstage, classified under Improper Neutralization of Special Elements in Output Used by a Downstream Component (Injection). CVSS score: 7.7/10. Published 2026-03-07.

How severe is CVE-2026-29186?

High severity. CVSS v3 base score is 7.7 out of 10.

Arbitrary file upload in Backstage

CVE-2026-29186

Backstage is an open framework for building developer portals. Prior to version 1.14.3, this is a configuration bypass vulnerability that enables arbitrary code execution. The @backstage/plugin-techdocs-node package uses an allowlist to fi…

EPSS: 0.008 (52.0th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.7 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:L/A:L.

Affected products

Backstage — versions < 1.14.3
Linuxfoundation Backstage_plugin-techdocs-node

Weakness classification (CWE)

References

security-advisories@github.com (x_refsource_CONFIRM, Vendor Advisory)
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Frequently asked questions

What is CVE-2026-29186?: CVE-2026-29186 is a high-severity vulnerability in Backstage, classified under Improper Neutralization of Special Elements in Output Used by a Downstream Component (Injection). CVSS score: 7.7/10. Published 2026-03-07.
How severe is CVE-2026-29186?: High severity. CVSS v3 base score is 7.7 out of 10.