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Fencer Intel
medium 6.3

CVE-2026-106559 json

Backstage: Improper input validation in Confluence to Markdown scaffolder module

published last mo. modified 24d ago also GHSA-75qf-886x-5xf2 , EUVD-2026-94372

cvss
6.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 26%
public exploits
0
none known

Summary

Backstage is an open framework for building developer portals. Prior to 0.3.25, the @backstage/plugin-scaffolder-backend-module-confluence-to-markdown package is affected by improper input validation in confluence to markdown scaffolder module. Insufficient input validation in the Confluence to Markdown scaffolder module could allow an attacker to influence file write operations during template execution. Exploitation requires a Backstage user to run a template that processes attacker-influenced Confluence content. This issue is fixed in version 0.3.25.

Patch / fix

  • npm @backstage/plugin-scaffolder-backend-module-confluence-to-markdown 0.3.25
  • linuxfoundation backstage/plugin-scaffolder-backend-module-confluence-to-markdown 0.3.25
  • linuxfoundation backstage 1.54.6

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CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
last mo.

Exploit prediction

0.33% chance of exploitation in the next 30 days, higher than 26% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 3.1 6.3 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:H/A:L
NVD 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
GitHub 3.1 6.3 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:H/A:L

Affected packages

ecosystem package affected fixed in
npm @backstage/plugin-scaffolder-backend-module-confluence-to-markdown
<0.3.25
0.3.25

Affected products

  • backstage backstage
  • @backstage plugin-scaffolder-backend-module-confluence-to-markdown

Classification

Weakness
  • CWE-22 Improper Limitation of a Pathname to a Restricted Directory
  • CWE-73 External Control of File Name or Path

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.