CVE-2026-106558

high

Description

Backstage is an open framework for building developer portals. Prior to 1.14.8, 1.15.6, and 2.0.1, the @backstage/plugin-techdocs-node package improperly validated mapping-style markdown_extensions configuration. An authenticated attacker who can register or influence an SCM-backed documentation source may bypass TechDocs sanitization and cause Python objects to be imported and instantiated in the generator runtime, leading to arbitrary code execution. Earlier fixes in versions 1.14.6 and 1.15.4 did not fully address the supported mapping representation of markdown_extensions. Impact is greatest when documentation generation runs with backend credentials, filesystem access, or internal network access. This issue is fixed in versions 1.14.8, 1.15.6, and 2.0.1.

References

https://github.com/backstage/backstage/security/advisories/GHSA-qmw3-745m-w99g

https://github.com/backstage/backstage/releases/tag/v1.55.2

https://github.com/backstage/backstage/releases/tag/v1.54.9

https://github.com/backstage/backstage/releases/tag/v1.50.7

https://github.com/backstage/backstage/commit/f18e9abcc6051491862b15e4fc60e69f8d52310c

https://github.com/backstage/backstage/commit/944edb51c8524d3664b18f2d57ba101b1c93b709

https://github.com/backstage/backstage/commit/32723a0fe4e12ed80535fc65d5331765c55aa91b

https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-94371

Details

Source: Mitre, NVD

Published: 2026-10-07

Updated: 2026-10-10

Risk Information

CVSS v2

Base Score: 9

Vector: CVSS2#AV:N/AC:L/Au:S/C:C/I:C/A:C

Severity: High

CVSS v3

Base Score: 8.8

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

Severity: High

EPSS

EPSS: 0.00471