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Vulnerabilities

Security fix · CVE-2026-106491

Backstage is an open framework for building developer portals.

Published Oct 6, 2026 · catalog updated Oct 22, 2026 · Backstage is an open

Last checked Oct 25, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2026-106491. EPSS is 0.27%. Act only if a listed version of Backstage is an open is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (Backstage is an open).
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Medium6.4
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.27%
Remediation
Version ranges on file
Affected products
cpe linuxfoundation/backstage · cpe linuxfoundation/backstage/plugin-proxy-backend

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe linuxfoundation/backstage< 1.54.6
  • cpe linuxfoundation/backstage/plugin-proxy-backend< 0.6.17

How to fix CVE-2026-106491

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-106491. EPSS is 0.27%. Act only if a listed version of Backstage is an open is installed.

Which versions are affected?

Compare what you have installed with < 1.54.6, < 0.6.17. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-20: Improper Input Validation; CWE-22: Path Traversal. EPSS 0.27%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Oct 6, 2026 · NIST NVD

    Detected

    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

  2. Oct 22, 2026 · NIST NVD

    Updated

    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

Sources

  • CVE.orgVulnerability recordCVE-2026-106491

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-106491

    30-day exploitation probability 0.27%

    first.org
  • NIST NVDVulnerability recordCVE-2026-106491

    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 forwar

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 25, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • FIRST EPSSOct 25, 2026
  • CVE.orgOct 23, 2026
  • NIST NVDOct 22, 2026