Backstage: Improper input validation in TechDocs MkDocs configuration

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-88064
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-16 15:18:04 UTC
Updated2026-09-16 16:17:19 UTC
DescriptionBackstage 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.

Risk And Classification

Primary CVSS: v3.1 8.8 HIGH from [email protected]

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Problem Types: CWE-20 | CWE-1336 | CWE-20 CWE-20: Improper Input Validation | CWE-1336 CWE-1336: Improper Neutralization of Special Elements Used in a Template Engine

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary8.8HIGHCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
3.1CNADECLARED8.8HIGHCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Backstage Backstage affected < 1.14.6 Not specified
CNA Backstage Backstage affected >= 1.15.0, < 1.15.4 Not specified

References

ReferenceSourceLinkTags
github.com/backstage/backstage/commit/02cd7cdbb18b687446277b5602adaee7f1... [email protected] github.com
github.com/backstage/backstage/commit/25125ee727a3de3418a8fa6a9e458cd5b7... [email protected] github.com
github.com/backstage/backstage/releases/tag/v1.50.5 [email protected] github.com
github.com/backstage/backstage/security/advisories/GHSA-292q-8mf5-h6g3 [email protected] github.com
github.com/backstage/backstage/commit/017ace52d9b327ededc6704cf17799c875... [email protected] github.com
github.com/backstage/backstage/commit/a900a9953c8f7ad3ba1906d1d257725a99... [email protected] github.com
github.com/backstage/backstage/releases/tag/v1.54.6 [email protected] github.com
github.com/backstage/backstage/commit/a7d995f11a5d27f0efbdbe8bb6c21b0698... [email protected] github.com
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