How severe is CVE-2026-106459?

CVE-2026-106459 has a CVSS score of 8.5/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by CVE-2026-106459?

CVE-2026-106459 affects the following packages: @backstage/plugin-scaffolder-backend-module-sentry (npm). Ecosystems affected: npm.

How do I fix CVE-2026-106459?

Update @backstage/plugin-scaffolder-backend-module-sentry to 0.3.8 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-106459 is resolved across your whole dependency graph.

How do I detect CVE-2026-106459 in my npm dependencies?

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

How do I mitigate CVE-2026-106459 if there is no patch (or I can't update yet)?

Restrict outbound requests from the affected component to an allowlist of hosts, block access to link-local and internal address ranges at the network layer, and require authentication on internal services so a forged request cannot reach them unauthenticated.

Is CVE-2026-106459 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-106459 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-2026-106459?

CVE-2026-106459 has an EPSS (Exploit Prediction Scoring System) score of 0.2%, placing it in the 11th 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-2026-106459?

CVE-2026-106459 is classified as Information Exposure (CWE-200), Server-Side Request Forgery (SSRF) (CWE-918). These weakness types describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2026-106459 published, and has it been updated?

CVE-2026-106459 was published on October 6, 2026 and was last updated on October 15, 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-2026-106459 — @backstage/plugin-scaffol…

HIGHFix: backstage/backstage@b0170fa

CVE-2026-106459 is a high-severity (CVSS 8.5) Information Exposure vulnerability in @backstage/plugin-scaffolder-backend-module-sentry. A fix is available for @backstage/plugin-scaffolder-backend-module-sentry — see the affected versions and patch details below.

Backstage: Improper input validation in Sentry scaffolder actions

Also known asGHSA-g734-fhp4-7mfp

Published

Oct 6, 2026

Updated

Oct 15, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Oct 18, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

0.2%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs11th percentile — riskier than 11% of all scored CVEsHighest risk

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

How urgent is this, really

CVE-2026-106459 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 394,415 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.

0other npm packages depend on this — each one inherits the vulnerability until it's patched upstream

@backstage/plugin-scaffolder-backend-module-sentrynpm

587downloads / week

Description

Impact

An authenticated internal user who can execute the affected actions may cause the backend to contact unintended destinations and disclose Sentry integration credentials. Subsequent impact depends on network reachability and the privileges granted to the configured token.

Patches

Upgrade @backstage/plugin-scaffolder-backend-module-sentry to version 0.3.8 or later. The fixed package is available in Backstage v1.54.8 and Backstage v1.55.0.

The update removes custom action-level apiBaseUrl values. Move any such value to scaffolder.sentry.apiBaseUrl before upgrading.

Workarounds

Disable the affected actions until the patched package is deployed.
Restrict scaffolder.action.execute permission for the affected Sentry actions to trusted users and templates.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`@backstage/plugin-scaffolder-backend-module-sentry`	≥ 0.3.0&&< 0.3.8	0.3.8`npm install @backstage/plugin-scaffolder-backend-module-sentry@0.3.8`

Affected Products

2 products · 2 configurations

Application

backstagelinuxfoundation

≥ 1.47.0 && < 1.54.8

range

Application

backstage\/plugin-scaffolder-backend-module-sentrylinuxfoundation

≥ 0.3.0 && < 0.3.8

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-module-sentry, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update @backstage/plugin-scaffolder-backend-module-sentry to 0.3.8 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-106459 is resolved across your whole dependency graph.
Workarounds
Restrict outbound requests from the affected component to an allowlist of hosts, block access to link-local and internal address ranges at the network layer, and require authentication on internal services so a forged request cannot reach them unauthenticated.

Frequently Asked Questions

### Impact An authenticated internal user who can execute the affected actions may cause the backend to contact unintended destinations and disclose Sentry integration credentials. Subsequent impact depends on network reachability and the privileges granted to the configured token. ### Patches Upgrade `@backstage/plugin-scaffolder-backend-module-sentry` to version `0.3.8` or later. The fixed package is available in [Backstage v1.54.8](https://github.com/backstage/backstage/releases/tag/v1.54.8) and [Backstage v1.55.0](https://github.com/backstage/backstage/releases/tag/v1.55.0). The update