CVE-2026-29186
Linuxfoundation Backstage Plugin-Techdocs-Node ≤ 1.14.3
Raw vector
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:L/A:LSummary
CVE-2026-29186 is a high-severity Injection (CWE-74) vulnerability in Linuxfoundation Backstage Plugin-Techdocs-Node. Its CVSS base score is 7.7 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked in the top 47% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified map to SI-10 (Information Input Validation) and SI-3 (Malicious Code Protection) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2026-29186 is a configuration bypass vulnerability in the @backstage/plugin-techdocs-node package of Backstage, an open framework for building developer portals. Affecting versions prior to 1.14.3, the flaw stems from a gap in the allowlist used to filter dangerous MkDocs configuration keys during the TechDocs documentation build process. This allows attackers to craft a malicious mkdocs.yml file that triggers arbitrary Python code execution, fully bypassing TechDocs' security controls. The vulnerability is rated 7.7 on the CVSS 3.1 scale (AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:L/A:L) and is associated with CWEs-74 (Improper Neutralization of Special Elements used in an SQL Command) and CWE-434 (Unrestricted Upload of File with Dangerous Type).
An attacker with low privileges, such as a authenticated user able to submit or influence TechDocs documentation builds over the network, can exploit this vulnerability despite its high attack complexity and lack of user interaction requirements. By exploiting the allowlist gap, the attacker achieves arbitrary Python code execution on the server during the MkDocs build process, potentially leading to high confidentiality impacts, scope changes, and limited integrity or availability disruptions.
The GitHub Security Advisory (GHSA-928r-fm4v-mvrw) confirms the issue has been patched in Backstage version 1.14.3, recommending immediate upgrades to mitigate the risk of arbitrary code execution.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-10146
Vulnerability Data
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 filter dangerous MkDocs configuration keys during the documentation build…
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process. A gap in this allowlist allows attackers to craft an mkdocs.yml that causes arbitrary Python code execution, completely bypassing TechDocs' security controls. This issue has been patched in version 1.14.3.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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V5.1.1V1.2.1V1.2.3V1.2.5
Mitigating Controls (NIST 800-53 r5) AI
SI-10 directly requires validation of information inputs to reject malformed or special-element content before it reaches downstream parsers.
Malicious-code protection at entry points blocks dangerous file types from being accepted and executed.
Least functionality restricts the file types and automatic processing capabilities the system will accept.
Mobile-code controls define, authorize, and block unacceptable uploaded code before automatic processing occurs.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Restricting execution of unauthorized software directly blocks dangerous uploaded files from running.
Secure SDLC practices directly require input validation and output encoding that prevent injection flaws.
Hardened configuration baselines can enforce allowed file types and processing rules.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Security testing in development catches injection vulnerabilities before release.
Logging supports detection of injection attempts but does not prevent the weakness.
Monitoring activities can identify active injection attacks after they occur.
Secure development life cycle mandates input validation and output encoding that directly prevent injection flaws.
Application security requirements explicitly call for controls against injection attacks in software design.
Secure architecture principles reduce injection surfaces but do not prescribe specific neutralization techniques.