Security Digest · Vulnerability record
CVE-2026-106501: Backstage: Sensitive information exposure in Scaffolder
Backstage is an open framework for building developer portals.
CVSS 9.6 Critical EPSS 0.5% · p41
Should you act?
Critical, preconditions apply
Severe if exploited, but exploitation needs conditions that may not apply to you. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.
- No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
- EPSS 0.5%, percentile 41: FIRST’s model estimates a 0.5% chance of exploitation activity in the next 30 days, higher than 41% of all scored CVEs (low). EPSS is a probability, not a verdict.
- Needs an account (low (any account)). Exposure depends on who can log in.
- Only applies if your dependency tree includes
@backstage/plugin-scaffolder-backend(npm) < 3.3.1, fixed in 3.3.1;@backstage/plugin-scaffolder-backend(npm) >= 3.4.0, < 3.4.1, fixed in 3.4.1;@backstage/plugin-scaffolder-backend(npm) >= 4.0.0, < 4.0.3, fixed in 4.0.3;@backstage/plugin-scaffolder-backend(npm) >= 4.0.4, < 4.1.0, fixed in 4.1.0. Check your lockfile, including transitive dependencies.
What it is
Backstage is an open framework for building developer portals. Prior to 3.3.1, 3.4.1, 4.0.3 and 4.1.0, the @backstage/plugin-scaffolder-backend package is affected by sensitive information exposure in scaffolder. An authenticated Backstage user who can read another user's Scaffolder task may receive internal execution data. In deployments where that data contains credentials for an external service, this may permit disclosure and unauthorized changes in that external service. This issue is fixed in versions 3.3.1, 3.4.1, 4.0.3 and 4.1.0.
From the GitHub advisory
Impact
An authenticated Backstage user who can read another user's Scaffolder task may receive internal execution data. In deployments where that data contains credentials for an external service, this may permit disclosure and unauthorized changes in that external service.
Patches
Patched in @backstage/plugin-scaffolder-backend version 4.1.0
Workarounds
Weakness type: CWE-200, CWE-201.
Product: @backstage/plugin-scaffolder-backend (npm) · Assigned by: GitHub_M · Published: 2026-10-06
Affected and fixed versions
| Ecosystem | Package | Vulnerable | First fixed |
|---|---|---|---|
| npm | @backstage/plugin-scaffolder-backend | < 3.3.1 | 3.3.1 |
| npm | @backstage/plugin-scaffolder-backend | >= 3.4.0, < 3.4.1 | 3.4.1 |
| npm | @backstage/plugin-scaffolder-backend | >= 4.0.0, < 4.0.3 | 4.0.3 |
| npm | @backstage/plugin-scaffolder-backend | >= 4.0.4, < 4.1.0 | 4.1.0 |
| Vendor | Product | Affected versions (per CVE record) |
|---|---|---|
| backstage | backstage | < 1.49.6, >= 1.50.0-next.0, < 1.50.5, >= 1.51.0-next.0, < 1.54.6 |
| @backstage | plugin-scaffolder-backend | < 3.3.1, >= 3.4.0, < 3.4.1, >= 4.0.0, < 4.0.3, >= 4.0.4, < 4.1.0 |
Severity scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_M | 3.1 | 9.6 Critical | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N |
| GitHub | 3.1 | 9.6 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N |
- Attack vector: network (remotely reachable)
- Attack complexity: low
- Privileges required: low (any account)
- User interaction: none
- Scope: changed (can affect other components)
CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.
Exploitation and urgency
- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation none, automatable no, technical impact total.
- FIRST EPSS (model of 2026-10-21): 0.48% probability of exploitation activity in the next 30 days; percentile 41.
Timeline
- — CVE record published by GitHub_M
- — CVE record last updated
- — GitHub-reviewed advisory GHSA-g2v8-7jhw-pp8p published (critical)
Sources and references
Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.
Vulnerability records
- GitHub Advisory GHSA-g2v8-7jhw-pp8p github.com
- CVE.org record CVE-2026-106501 cve.org
- NVD entry CVE-2026-106501 nvd.nist.gov
Other references from the CVE record and advisory
- github.com github.com
- github.com github.com
- github.com github.com
- github.com github.com
- github.com github.com
- github.com github.com
- github.com github.com