Medium
Backstage: Improper input validation in proxy-backend
Type: advisorySources: OSV
Backstage is an open framework for building developer portals. Prior to 0.6.17, the @backstage/plugin-proxy-backend package is affected by improper input validation in proxy-backend. An authenticated Backstage user could craft a request URL that causes the proxy-backend to forward the request to a path outside the configured base path on the target server. This is limited to target servers already configured as proxy endpoints and requires Backstage authentication by default. This issue is fixed in version 0.6.17.
- Products
- Not specified
- Affected versions
- Not specified
- Fixed versions
- Not specified
- CVEs
- CVE-2026-106491
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 4 Nov 2026, 11:44 UTC · Revision 1
Source evidence
Backstage: Improper input validation in proxy-backend
core-osv · Original sourcePublished 6 Oct 2026, 20:45 UTC
Backstage is an open framework for building developer portals. Prior to 0.6.17, the @backstage/plugin-proxy-backend package is affected by improper input validation in proxy-backend. An authenticated Backstage user could craft a request URL that causes the proxy-backend to forward the request to a path outside the configured base path on the target server. This is limited to target servers already configured as proxy endpoints and requires Backstage authentication by default. This issue is fixed in version 0.6.17.
osv:CVE-2026-106491
Complete source record
{
"id": "eb540b03275a5f16852251f7a291b8441efb37955f0b53815deb27aa5c0a242f",
"url": "https://osv.dev/vulnerability/CVE-2026-106491",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "Backstage: Improper input validation in proxy-backend",
"summary": "Backstage is an open framework for building developer portals. Prior to 0.6.17, the @backstage/plugin-proxy-backend package is affected by improper input validation in proxy-backend. An authenticated Backstage user could craft a request URL that causes the proxy-backend to forward the request to a path outside the configured base path on the target server. This is limited to target servers already configured as proxy endpoints and requires Backstage authentication by default. This issue is fixed in version 0.6.17.",
"evidence": "osv:CVE-2026-106491",
"products": [],
"severity": "medium",
"structured": {
"id": "CVE-2026-106491",
"aliases": [
"CVE-2026-106491",
"GHSA-9ghw-48h5-v2w5"
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"modified": "2026-10-28T02:30:34.875611601Z",
"provider": "osv",
"references": [
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"https://nvd.nist.gov/vuln/detail/CVE-2026-106491",
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],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 502144,
"published_at": "2026-10-06T20:45:08.067+00:00"
}