7.7
HIGH CVSS 3.1
CVE-2026-106509
Backstage: Improper validation of MkDocs theme configuration in TechDocs
Description

Backstage is an open framework for building developer portals. Prior to 1.14.6, the @backstage/plugin-techdocs-node package is affected by improper validation of mkdocs theme configuration in techdocs. When TechDocs is configured to build documentation locally or in a container, a user with write access to a registered repository can include configuration values in mkdocs.yml that cause arbitrary code execution during the documentation build process. This issue is fixed in versions 1.14.6 and 1.15.4.

INFO

Published Date :

Oct. 6, 2026, 10:17 p.m.

Last Modified :

Oct. 6, 2026, 10:17 p.m.

Remotely Exploit :

Yes !
Affected Products

The following products are affected by CVE-2026-106509 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Linuxfoundation backstage_plugin-techdocs-node
CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 3.1 HIGH MITRE-CVE
CVSS 3.1 HIGH [email protected]
Solution
Update the @backstage/plugin-techdocs-node package to version 1.14.6 or later.
  • Update to version 1.14.6 or 1.15.4.
  • Review mkdocs.yml for malicious configurations.
  • Apply necessary security patches.
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-106509 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-106509 weaknesses.

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2026-106509 vulnerability anywhere in the article.

The following table lists the changes that have been made to the CVE-2026-106509 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • New CVE Received by [email protected]

    Oct. 06, 2026

    Action Type Old Value New Value
    Added Description Backstage is an open framework for building developer portals. Prior to 1.14.6, the @backstage/plugin-techdocs-node package is affected by improper validation of mkdocs theme configuration in techdocs. When TechDocs is configured to build documentation locally or in a container, a user with write access to a registered repository can include configuration values in mkdocs.yml that cause arbitrary code execution during the documentation build process. This issue is fixed in versions 1.14.6 and 1.15.4.
    Added CVSS V3.1 AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:L/A:L
    Added CWE CWE-94
    Added CWE CWE-1336
    Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/106xxx/CVE-2026-106509.json">CVE-2026-106509</a>
    Added Reference https://github.com/backstage/backstage/commit/02cd7cdbb18b687446277b5602adaee7f1d53cbb
    Added Reference https://github.com/backstage/backstage/commit/a900a9953c8f7ad3ba1906d1d257725a9996cc9d
    Added Reference https://github.com/backstage/backstage/releases/tag/v1.50.5
    Added Reference https://github.com/backstage/backstage/releases/tag/v1.54.6
    Added Reference https://github.com/backstage/backstage/security/advisories/GHSA-8w7q-29mw-gf5c
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.