CVE-2026-106504 — Backstage: Sensitive information exposure in scaffolder task logs

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

• Documented patch — github.com (NIST National Vulnerability Database)
• Documented patch — github.com (NIST National Vulnerability Database)
• Documented mitigation — github.com (NIST National Vulnerability Database)
• Npm @backstage/plugin-scaffolder-backend: fixed in version 4.1.0 — github.com (GitHub Security Advisories)

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

1. Identify exposed assets running the affected vendor/product/version combinations (@backstage Backstage, @backstage Plugin-scaffolder-backend, Linuxfoundation Backstage…).
2. Apply the fixed version or the patch documented under Remediation.
3. Search available logs for exploit probes matching the vulnerability class (info disclosure), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-532 · Insertion of Sensitive Information into Log File

Other CVEs with this weakness →

EPSS over time FIRST

Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 0.26%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

• Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
• Look for anomalous data read/export volumes and access to sensitive records.

Timeline

What happened to this CVE, newest first.

• 2026
• Fix documented
  Oct 13, 2026 · GitHub Security Advisories
• Affected products added · npm/@backstage/plugin-scaffolder-backend
  Oct 13, 2026 · GitHub Security Advisories
• Fix documented
  Oct 13, 2026 · NIST National Vulnerability Database
• Affected products added · linuxfoundation/backstage/plugin-scaffolder-backend, linuxfoundation/backstage
  Oct 13, 2026 · NIST National Vulnerability Database
• Source status changed · Undergoing Analysis → Analyzed
  Oct 13, 2026 · NIST National Vulnerability Database
• Affected products added · backstage/backstage, @backstage/plugin-scaffolder-backend
  Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
• SSVC assessment updated
  Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
• Record published
  Oct 13, 2026
• CVSS changed · 6.5
  Oct 13, 2026 · NIST National Vulnerability Database
• Source status changed · → Undergoing Analysis
  Oct 13, 2026 · NIST National Vulnerability Database
• Record created in this database
  Oct 13, 2026 · NIST National Vulnerability Database
• CVE published
  Oct 6, 2026 · GitHub_M

Source activity

Repeated readings are counted rather than listed.

• 1× References added · Oct 13, 2026 – Oct 13, 2026
• 1× Official description updated · Oct 13, 2026 – Oct 13, 2026

References

5 on the record

• github.com/backstage/backstage/security/advisories/GHSA-4xvq-3m68-h444
  x_refsource_CONFIRM, Mitigation, Vendor Advisory, NIST National Vulnerability Database
• github.com/backstage/backstage/releases/tag/v1.54.6
  x_refsource_MISC, Patch, Release Notes, NIST National Vulnerability Database
• github.com/backstage/backstage/commit/3eb3dc59eb0da0deccd532f19eb460bb452c9efb
  x_refsource_MISC, Patch, NIST National Vulnerability Database
• github.com/advisories/GHSA-4xvq-3m68-h444
  GitHub Security Advisories
• nvd.nist.gov/vuln/detail/CVE-2026-106504
  GitHub Security Advisories

Elsewhere on this site

Related CVEs (same products)

• Medium CVE-2026-106495 Backstage: Improper access control in backend action invocation 3d
• High CVE-2026-106557 Backstage: Improper input validation in TechDocs Markdown extension configuration 8d
• Medium CVE-2026-106559 Backstage: Improper input validation in Confluence to Markdown scaffolder module 8d
• High CVE-2026-106560 Backstage: Improper repository path validation in a Scaffolder backend module 8d
• Medium CVE-2026-106563 Backstage: Improper entity validation in deprecated Kubernetes services endpoint 8d
• Medium CVE-2026-106562 Backstage: Incorrect authorization in search engine permission filtering 8d

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

• No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
• No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
• No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-106504 is "Backstage: Sensitive information exposure in scaffolder task logs", rated Medium. It affects Backstage (@backstage); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 6.5 describes technical severity. EPSS 0.26% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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