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Fencer Vulns
medium 4.9

CVE-2026-106499 json

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

published 2026-10-06 33 d ago modified 2026-10-15 25 d ago also GHSA-mfvq-x7vr-rgqg , EUVD-2026-94057

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 1.54.6

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
32 d ago

Exploit prediction

0.27% chance of exploitation in the next 30 days, higher than 19% of all scored CVEs (FIRST EPSS, 2026-11-08).

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 Vulns 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.