How severe is GHSA-3xr5-8w6c-p5gw?

GHSA-3xr5-8w6c-p5gw has a CVSS score of 4.3/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by GHSA-3xr5-8w6c-p5gw?

GHSA-3xr5-8w6c-p5gw affects the following packages: @backstage/backend-defaults (npm). Ecosystems affected: npm.

How do I fix GHSA-3xr5-8w6c-p5gw?

Update @backstage/backend-defaults to 0.17.8 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-3xr5-8w6c-p5gw is resolved across your whole dependency graph.

How do I detect GHSA-3xr5-8w6c-p5gw in my npm dependencies?

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

How do I mitigate GHSA-3xr5-8w6c-p5gw if there is no patch (or I can't update yet)?

Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.

Is GHSA-3xr5-8w6c-p5gw actively exploited in the wild?

No public exploit code has been indexed for GHSA-3xr5-8w6c-p5gw 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 GHSA-3xr5-8w6c-p5gw?

GHSA-3xr5-8w6c-p5gw has an EPSS (Exploit Prediction Scoring System) score of 0.2%, placing it in the 14th 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 GHSA-3xr5-8w6c-p5gw?

GHSA-3xr5-8w6c-p5gw is classified as CWE-284 (CWE-284). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was GHSA-3xr5-8w6c-p5gw published, and has it been updated?

GHSA-3xr5-8w6c-p5gw was published on October 15, 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

MEDIUM severity

Backstage: Improper access control in backend action invocationGHSA-3xr5-8w6c-p5gw

MEDIUMFix: backstage/backstage@a8fb34a

GHSA-3xr5-8w6c-p5gw is a medium-severity (CVSS 4.3) CWE-284 vulnerability in @backstage/backend-defaults. A fix is available for @backstage/backend-defaults — see the affected versions and patch details below.

Also known asCVE-2026-106495

Published

Oct 15, 2026

Updated

Oct 15, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

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

Exploitation Status

No confirmed exploitation observed yet

CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for GHSA-3xr5-8w6c-p5gw.

EPSS Exploitation Probability

via FIRST.org ↗

0.2%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs14th percentile — riskier than 14% of all scored CVEsHighest risk

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

How urgent is this, really

GHSA-3xr5-8w6c-p5gw 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.

255other npm packages depend on this — each one inherits the vulnerability until it's patched upstream

@backstage/backend-defaultsnpm

175Kdownloads / week

Description

Backstage is an open framework for building developer portals. Prior to 0.17.8, the @backstage/backend-defaults package is affected by improper access control in backend action invocation. An authenticated user could invoke actions that an operator had excluded through action configuration. Existing action permissions and downstream authorization remain enforced. This issue is fixed in version 0.17.8.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`@backstage/backend-defaults`	all versions	0.17.8`npm install @backstage/backend-defaults@0.17.8`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @backstage/backend-defaults, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update @backstage/backend-defaults to 0.17.8 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-3xr5-8w6c-p5gw is resolved across your whole dependency graph.
Workarounds
Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.

Frequently Asked Questions

### Impact An authenticated user could invoke actions that an operator had excluded through action configuration. Existing action permissions and downstream authorization remain enforced. ### Patches Patched in `@backstage/backend-defaults` version `0.17.8` ### Workarounds Limit access to action invocation endpoints to trusted service callers until upgrading.