CVE-2026-106491: Backstage is an open framework for building developer portals

Q: How do I fix CVE-2026-106491?

backstage\/plugin-proxy-backend: upgrade to 0.6.17; backstage: upgrade to 1.54.6. Exact commands for each OS are on this page.

Q: Is CVE-2026-106491 being exploited?

CVE-2026-106491 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-106491 affect?

CVE-2026-106491 affects backstage\/plugin-proxy-backend, backstage. Severity is medium (CVSS 6.4). 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

Q: How urgent is CVE-2026-106491?

Priority 32/100. On your watchlist

Routine

MEDIUM 6.4WATCHLISTUPGRADEUPGRADE

CVE-2026-106491 is a medium-severity flaw (CVSS 6.4) affecting backstage\/plugin-proxy-backend, backstage. 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 0.6.17, 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 Backst

Why this priority

On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	6.4 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.3% (top 80%)
CISA exploited list	No
Weakness	CWE-20, CWE-22
Published	2026-10-06
Last modified	2026-10-22

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

Last updated 2026-10-22 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-10-06 21:17 UTCPublished CVE record published
2026-10-22 14:10 UTCUpdated Record last modified

linuxfoundation backstage\/plugin-proxy-backend UPGRADE

Affected: < 0.6.17

Fixed in: 0.6.17

Safe to downgrade to: no unaffected older release

1. Check installed version

npm ls backstageplugin-proxy-backend

2. UPGRADE to 0.6.17

npm install backstageplugin-proxy-backend@">=0.6.17"

linuxfoundation backstage UPGRADE

Affected: < 1.54.6

Fixed in: 1.54.6

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy backstage || rpm -q backstage || backstage --version

2. UPGRADE to 1.54.6 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade backstage

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade backstage

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

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-2026-106491?

backstage\/plugin-proxy-backend: upgrade to 0.6.17; backstage: upgrade to 1.54.6. Exact commands for each OS are on this page.

Is CVE-2026-106491 being exploited?

CVE-2026-106491 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-2026-106491 affect?

CVE-2026-106491 affects backstage\/plugin-proxy-backend, backstage. Severity is medium (CVSS 6.4). 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

How urgent is CVE-2026-106491?

Priority 32/100. On your watchlist

References

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