TI-2026-23303 Aliases CVE-2026-29186 GHSA-928r-fm4v-mvrw

@backstage/plugin-techdocs-node: TechDocs Mkdocs Configuration Key Enables Arbitrary Code Execution

MEDIUM 44CWE-434Published 2026-03-07 · Updated 2026-07-15

Key facts

Attack vector: Network
Privileges required: None
User interaction: None
Attack complexity: Low
Impact type: Code execution
Confidentiality · integrity · availability: High · High · High
Fix status: Partial Red Hat: 2 fixed, 1 without a fix

Attack profile from CVSS 3.1 · NVD. Fix status from CNA, GitHub and Red Hat. Impact type from CWE-434.

Summary

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 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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.0087 59th percentileScored 2026-11-07

Fix Partial backstage (backstage): 1.14.3@backstage/plugin-techdocs-node (npm): 1.14.3Red Hat: 2 advisoriesRed Hat: 2 fixed, 1 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: None
Automatable: No
Technical impact: Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
backstage	backstage	before 1.14.3	1.14.3	Patch available	CNA
—	@backstage/plugin-techdocs-node (npm)	before 1.14.3	1.14.3	Patch available	GHSA-928r-fm4v-mvrw

backstage Vendorbackstage Affected before 1.14.3 Fixed in 1.14.3 Patch available CNA
@backstage/plugin-techdocs-node (npm) Vendor— Affected before 1.14.3 Fixed in 1.14.3 Patch available GHSA-928r-fm4v-mvrw

CPE configurations NVD · 1

CPE	Versions	Role	Vendor
cpe:2.3:a:linuxfoundation:backstage_plugin-techdocs-node::::::::	before 1.14.3	Vulnerable	backstage

cpe:2.3:a:linuxfoundation:backstage_plugin-techdocs-node:*:*:*:*:*:*:*:* Versions before 1.14.3 Vulnerable ·backstage

Remediation

Fix · CNA backstage (backstage) Fixed in 1.14.3
Fix · GHSA-928r-fm4v-mvrw @backstage/plugin-techdocs-node (npm) Fixed in 1.14.3 Advisory →

Red Hat 2 advisories

RHSA-2026:13826 Released 2026-05-05 · Red Hat rating Critical
Red Hat Developer Hub 1.9.4 release.
- Red Hat Developer Hub 1.9 registry.redhat.io/rhdh/rhdh-hub-rhel9, registry.redhat.io/rhdh/rhdh-rhel9-operator
RHSA-2026:9742 Released 2026-04-22 · Red Hat rating Critical
Red Hat Developer Hub 1.8.6 release.
- Red Hat Developer Hub 1.8 registry.redhat.io/rhdh/rhdh-hub-rhel9, registry.redhat.io/rhdh/rhdh-rhel9-operator

Vendor assessments

Red Hat

Red Hat rating: Important. Red Hat's page for this CVE →

Product	Status	Plan or fix
Self-service automation portal 2	Affected	No fix yet
Red Hat Developer Hub 1.8	Fixed	RHSA-2026:9742
Red Hat Developer Hub 1.9	Fixed	RHSA-2026:13826

Not affected: 2 products

Red Hat Developer Hub 1.8
Red Hat Developer Hub 1.9

Timeline

2026-10-02 Threatist record created from CVE-2026-29186
2026-10-03 Alias added: GHSA-928r-fm4v-mvrw

References

Advisory 2

Other 4

TI-2026-60083 Backstage: Improper input validation in TechDocs MkDocs configuration CVSS 3.1HIGH 8.8
TI-2026-69165 Backstage TechDocs config flaw allows code execution CVSS 3.1HIGH 8.8
TI-2026-69083 Code injection via MkDocs theme configuration in Backstage TechDocs CVSS 3.1HIGH 8.8
TI-2026-69079 Bypass of MkDocs config sanitizer in Backstage TechDocs backend CVSS 3.1HIGH 8.5
TI-2026-69157 Remote code execution in Backstage TechDocs via crafted mkdocs.yml CVSS 3.1HIGH 7.7
TI-2026-69051 Server-side request forgery in Backstage TechDocs MkDocs plugin CVSS 3.1HIGH 7.7

See all 9 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences