CVE-2026-73563: Backstage is an open framework for building developer portals

Routine

MEDIUM 4.7WATCHLISTUPGRADE

CVE-2026-73563 is a medium-severity flaw (CVSS 4.7) affecting backstage\/plugin-auth-backend. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Backstage is an open framework for building developer portals. Prior to 0.29.2, the experimental dynamic client registration and client ID metadata document features in the @backstage/plugin-auth-backend use full-string matcher.isMatch glob matching for auth.experimentalDynamicClientRegistration.allowedRedirectUriPatterns and the auth.experimentalClientIdMetadataDocuments allowedClientIdPatterns and allowedRedirectUriPatterns options. A hostname

Why this priority

On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	4.7 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	0.2% (top 93%)
CISA exploited list	No
Weakness	CWE-601
Published	2026-08-13
Last modified	2026-10-15

Publisher (CNA): GitHub, Inc. · Vendor: linuxfoundation

Last updated 2026-10-15 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-08-13 18:18 UTCPublished CVE record published
2026-10-15 20:37 UTCUpdated Record last modified

linuxfoundation backstage\/plugin-auth-backend UPGRADE

Affected: < 0.29.2

Fixed in: 0.29.2

Safe to downgrade to: no unaffected older release

1. Check installed version

npm ls backstageplugin-auth-backend

2. UPGRADE to 0.29.2

npm install backstageplugin-auth-backend@">=0.29.2"

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-73563?

backstage\/plugin-auth-backend: upgrade to 0.29.2. Exact commands for each OS are on this page.

Is CVE-2026-73563 being exploited?

CVE-2026-73563 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-73563 affect?

CVE-2026-73563 affects backstage\/plugin-auth-backend. Severity is medium (CVSS 4.7). Backstage is an open framework for building developer portals. Prior to 0.29.2, the experimental dynamic client registration and client ID metadata document features in the @backstage/plugin-auth-backend use full-string matcher.isMatch glob

How urgent is CVE-2026-73563?

Priority 23/100. On your watchlist

References

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