How severe is CVE-2026-106500?

CVE-2026-106500 has a CVSS score of 8.5/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by CVE-2026-106500?

CVE-2026-106500 affects the following packages: @backstage/plugin-scaffolder-backend (npm). Ecosystems affected: npm.

How do I fix CVE-2026-106500?

Update @backstage/plugin-scaffolder-backend to 4.1.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-106500 is resolved across your whole dependency graph.

How do I detect CVE-2026-106500 in my npm dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @backstage/plugin-scaffolder-backend, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2026-106500 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Is CVE-2026-106500 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-106500 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-106500?

CVE-2026-106500 has an EPSS (Exploit Prediction Scoring System) score of 0.3%, placing it in the 26th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-106500?

CVE-2026-106500 is classified as CWE-59 (CWE-59), CWE-362 (CWE-362). These weakness types describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2026-106500 published, and has it been updated?

CVE-2026-106500 was published on October 6, 2026 and was last updated on October 21, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

📦

📦 npm

Not in CISA KEV

HIGH severity

CVE-2026-106500 — @backstage/plugin-scaffol…

HIGHFix: backstage/backstage@0d24f1b

CVE-2026-106500 is a high-severity (CVSS 8.5) CWE-59 vulnerability in @backstage/plugin-scaffolder-backend. A fix is available for @backstage/plugin-scaffolder-backend — see the affected versions and patch details below.

Backstage: Improper task state validation in Scaffolder backend

Also known asGHSA-xvgh-hmx8-9xxf

Published

Oct 6, 2026

Updated

Oct 21, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Oct 23, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

0.3%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs26th percentile — riskier than 26% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

CVE-2026-106500 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 394,803 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

1 pkg affected

How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.

69other npm packages depend on this — each one inherits the vulnerability until it's patched upstream

@backstage/plugin-scaffolder-backendnpm

68Kdownloads / week

Description

Impact

An authenticated user with permission to create and access Scaffolder tasks may, under specific timing and deployment conditions, affect files accessible to the Backstage backend. If backend application files are writable, the confidentiality, integrity, and availability of the backend may be compromised.

Patches

Patched in @backstage/plugin-scaffolder-backend version 4.1.0

Workarounds

Restrict Scaffolder task creation and task-read permissions to trusted users through the permission policy.
Limit who can register or modify templates and which Scaffolder actions may execute.
Run backend application files read-only outside a dedicated, least-privilege Scaffolder working directory.

References

Authorizing Scaffolder tasks, parameters, steps, and actions

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`@backstage/plugin-scaffolder-backend`	all versions	4.1.0`npm install @backstage/plugin-scaffolder-backend@4.1.0`

Affected Products

2 products · 7 configurations

Application

backstagelinuxfoundation

≥ 1.51.0 && < 1.54.6

range

Application

backstage\/plugin-scaffolder-backendlinuxfoundation

≥ 4.0.4 && < 4.1.0

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @backstage/plugin-scaffolder-backend, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update @backstage/plugin-scaffolder-backend to 4.1.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-106500 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatImportant

This vulnerability is rated as Important severity because authenticated remote users with rights to run software templates can alter files within the backend service environment, posing a risk to data integrity and system confidentiality. While the flaw requires valid user credentials and specific Scaffolder…

Workaround published by Red Hat

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.

Source: Red Hat security advisory for CVE-2026-106500 (CC BY 4.0)

Frequently Asked Questions

### Impact An authenticated user with permission to create and access Scaffolder tasks may, under specific timing and deployment conditions, affect files accessible to the Backstage backend. If backend application files are writable, the confidentiality, integrity, and availability of the backend may be compromised. ### Patches Patched in `@backstage/plugin-scaffolder-backend` version `4.1.0` ### Workarounds - Restrict Scaffolder task creation and task-read permissions to trusted users through the permission policy. - Limit who can register or modify templates and which Scaffolder actions