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Vulnerability · Published Sep 16, 2026 · Assigned by GitHub_M

CVE-2026-88064Backstage: Improper input validation in TechDocs MkDocs configuration

High 8.8

In plain English

A high-severity improper input validation in backstage from backstage. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 1.2% (higher than 68% of all known vulnerabilities).

Severity (CVSS 3.1)8.8High
Exploit odds (30 days)1.2%top 32.2% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

Backstage is an open framework for building developer portals. Prior to 1.14.6 and from 1.15.0 until 1.15.4, the @backstage/plugin-techdocs-node package insufficiently validates mkdocs.yml supplied by an authenticated user who can register or modify a TechDocs source. Unsafe Python YAML tags, markdown_extensions names and configuration, theme options, and extra_templates values can reach the documentation generator and cause unintended code execution. The resulting impact is limited to the files, credentials, network access, and other resources available to the TechDocs backend or build container. This issue is fixed in versions 1.14.6 and 1.15.4.

Affected products (as reported)

VendorProductVersions
backstage backstage < 1.14.6>= 1.15.0, < 1.15.4

Weakness: CWE-20, CWE-1336 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

References