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Fencer Intel
medium 4.9

CVE-2026-106499 json

Backstage: Secret-derived values may be exposed in scaffolder task logs

published last mo. modified 26d ago also EUVD-2026-94057 , GHSA-mfvq-x7vr-rgqg

cvss
4.9
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 19%
public exploits
0
none known

Summary

Backstage is an open framework for building developer portals. Prior to 4.1.0, the @backstage/plugin-scaffolder-backend package could expose secret-derived values in Scaffolder task logs. Deployments that configure sensitive scaffolder.defaultEnvironment.secrets and allow an attacker to create or modify Scaffolder templates are affected. A template author could cause secret-derived values used during template iteration to be persisted and exposed to users who can access the resulting task logs. This issue is fixed in version 4.1.0.

Patch / fix

  • npm @backstage/plugin-scaffolder-backend 4.1.0
  • linuxfoundation @backstage/plugin-scaffolder-backend 4.1.0
  • linuxfoundation backstage/plugin-scaffolder-backend 4.1.0
  • linuxfoundation backstage_plugin-scaffolder-backend 4.1.0

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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-2026-106499 updated cvss 4.9

plugin-scaffolder-backend: Backstage: Information disclosure via secret leakage in Scaffolder task logs

  • Red Hat Developer Hub 1 rhdh/rhdh-hub-rhel9, rhdh/red-hat-developer-hub-backstage-plugin-orchestrator-backend Red Hat Self-service automation portal 2 ansible-automation-platform/automation-portal, ansible-automation-platform/bootc-automation-portal-rhel9
    affected: workaround, no fix available “Fix deferred”

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

0.27% chance of exploitation in the next 30 days, higher than 19% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 3.1 4.9 CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N
GitHub 3.1 4.9 CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N

Affected packages

ecosystem package affected fixed in
npm @backstage/plugin-scaffolder-backend
<4.1.0
4.1.0

Affected products

  • backstage backstage
  • @backstage plugin-scaffolder-backend

Classification

Weakness
  • CWE-532 Insertion of Sensitive Information into Log File

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.