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Fencer Intel
high 7.7

CVE-2026-106557 json

Backstage: Improper input validation in TechDocs Markdown extension configuration

published last mo. modified last mo. also EUVD-2026-94482 , GHSA-f7v3-xhm6-w245

cvss
7.7
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 31%
public exploits
0
none known

Summary

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.

Patch / fix

  • npm @backstage/plugin-techdocs-node 1.15.4
  • linuxfoundation @backstage/plugin-techdocs-node 1.14.6, 1.15.4
  • linuxfoundation backstage_plugin-techdocs-node 1.14.6, 1.15.4

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-106557 updated cvss 6.5

@backstage/plugin-techdocs-node: @backstage/plugin-techdocs-node: Information disclosure via improper Markdown extension configuration validation

  • Red Hat Developer Hub 1 rhdh/rhdh-hub-rhel9 Red Hat Self-service automation portal 2 ansible-automation-platform/automation-portal, ansible-automation-platform/bootc-automation-portal-rhel9
    affected: workaround, no fix available

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
last mo.

Exploit prediction

0.38% chance of exploitation in the next 30 days, higher than 31% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 3.1 7.7 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N
GitHub 3.1 7.7 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N

Affected packages

ecosystem package affected fixed in
npm @backstage/plugin-techdocs-node
<1.15.4
1.15.4

Affected products

  • backstage backstage
  • @backstage plugin-techdocs-node

Classification

Weakness
  • CWE-22 Improper Limitation of a Pathname to a Restricted Directory
  • CWE-918 Server-Side Request Forgery

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.