CVE-2026-106456: Backstage is an open framework for building developer portals

Routine

MEDIUM 4.8REMOTEWATCHLISTUPGRADEUPGRADE

CVE-2026-106456 is a medium-severity flaw (CVSS 4.8) 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. From 0.5.0 until 0.6.18, the @backstage/plugin-proxy-backend package is affected by inconsistent credential enforcement for overlapping proxy routes. An operator can configure overlapping proxy paths with different credential requirements. When a parent path permits unauthenticated access and a nested path requires credentials, the parent exemption can also cover requests handled by t

Why this priority

Remotely exploitable, no login, no user action
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	4.8 (Medium)
Attack vector	Network (remote)
Attack complexity	High
Privileges needed	None
User interaction	None
EPSS exploit chance	0.2% (top 85%)
CISA exploited list	No
Weakness	CWE-863
Published	2026-10-06
Last modified	2026-10-27

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

Last updated 2026-10-27 · 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
2026-10-27 20:51 UTCUpdated Record last modified

linuxfoundation backstage\/plugin-proxy-backend UPGRADE

Affected: >= 0.5.0 and < 0.6.18

Fixed in: 0.6.18

Safe to downgrade to: a release before 0.5.0

1. Check installed version

npm ls backstageplugin-proxy-backend

2. UPGRADE to 0.6.18

npm install backstageplugin-proxy-backend@">=0.6.18"

3. If no update is available yet, DOWNGRADE to a release before 0.5.0

npm view backstageplugin-proxy-backend versions npm install backstageplugin-proxy-backend@"<0.5.0"

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

linuxfoundation backstage UPGRADE

Affected: >= 1.28.0 and < 1.55.0

Fixed in: 1.55.0

Safe to downgrade to: a release before 1.28.0

1. Check installed version

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

2. UPGRADE to 1.55.0 (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.

3. If no update is available yet, DOWNGRADE to a release before 1.28.0 (Debian / Ubuntu)

apt-cache madison backstage sudo apt install backstage=<VERSION_BEFORE_1.28.0> sudo apt-mark hold backstage

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list backstage sudo dnf downgrade backstage-<VERSION_BEFORE_1.28.0> sudo dnf versionlock add backstage

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

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-2026-106456?

backstage\/plugin-proxy-backend: upgrade to 0.6.18; backstage: upgrade to 1.55.0. Exact commands for each OS are on this page.

Is CVE-2026-106456 being exploited?

CVE-2026-106456 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-2026-106456 affect?

CVE-2026-106456 affects backstage\/plugin-proxy-backend, backstage. Severity is medium (CVSS 4.8). Backstage is an open framework for building developer portals. From 0.5.0 until 0.6.18, the @backstage/plugin-proxy-backend package is affected by inconsistent credential enforcement for overlapping proxy routes. An operator can configure o

How urgent is CVE-2026-106456?

Priority 30/100. Remotely exploitable, no login, no user action; On your watchlist

Related CVEs

CVE-2026-106491 MEDIUM 6.4 UPGRADE UPGRADE Backstage is an open framework for building developer portals

References

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