What’s Vulnerable › Vulnerabilities

CVE-2026-106557: Backstage: Improper input validation in TechDocs Markdown extension configuration

• Severity: high (CVSS 7.7 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-07 · updated 2026-10-08
• Weakness: CWE-22

Description

Backstage is an open framework for building developer portals. Prior to 1.14.6 and 1.15.4, the @backstage/plugin-techdocs-node package did not sufficiently validate TechDocs Markdown extension configuration. An authenticated user who can register or modify documentation sources may cause a TechDocs build to access resources outside the intended documentation boundary, potentially exposing backend-host data or internal network resources. This issue is fixed in versions 1.14.6 and 1.15.4 when pymdown-extensions 10.21.3 or later is also used, normally through mkdocs-techdocs-core 1.7.0 or later.

Affected products

• backstage: before 1.50.5; from 1.51.0-next.0, < 1.54.6
• @backstage plugin-techdocs-node: before 1.14.6; from 1.15.0, < 1.15.4

References

• https://github.com/backstage/backstage/commit/017ace52d9b327ededc6704cf17799c875ae0f29
• https://github.com/backstage/backstage/commit/2d9de4ca117a529de4b6ed7dfb7aa507ca7b3f91
• https://github.com/backstage/backstage/releases/tag/v1.50.5
• https://github.com/backstage/backstage/releases/tag/v1.54.6
• https://github.com/backstage/backstage/security/advisories/GHSA-f7v3-xhm6-w245

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