CVE-2026-32235

mediumpriority · track · 19EPSS 0.001 · 4 %ileEUUS

grimoire priorityP3 · Track

Exploitable?

—

no known exploitation

Likely / severe?

0.14% (4th) EPSS

CVSS 4.7 · medium

Is it mine?

3 products

Check your exposure

Who says so?

4 sources

cnnvd · enisa_euvd · nvd · osv

EPSS · scored 2026-10-27

Backstage is an open framework for building developer portals. Prior to 0.27.1, the experimental OIDC provider in @backstage/plugin-auth-backend is vulnerable to a redirect URI allowlist bypass. Instances that have enabled experimental Dynamic Client Registration or Client ID Metadata Documents and configured allowedRedirectUriPatterns are affected. A specially crafted redirect URI can pass the allowlist validation while resolving to an attacker-controlled host. If a victim approves the resulting OAuth consent request, their authorization code is sent to the attacker, who can exchange it for a valid access token. This requires victim interaction and that one of the experimental features is explicitly enabled, which is not the default. This vulnerability is fixed in 0.27.1.

cvss

Technical severity, 0–10. One row per scoring source.

5.9

010

base score 0–10 · higher = more severe · hover a vector to decode

v3.14.7mediumCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:Nprimary · NVD / NIST USexploitability 1.6 · impact 2.7

v3.15.9mediumCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:L/A:Nsecondary · ENISA EU

v3.15.9mediumCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:L/A:Nsecondary · security-advisories@github.comexploitability 1.6 · impact 4.2

v3.15.9mediumCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:L/A:Nsecondary · OSV

v3.14.3mediumCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N/E:Usecondary · CVSS-BT (t0sche)

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Trackcoordinatorcisa_ssvcUS

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-20USCWE-601USCWE-601US

affected products (3)

Products and version ranges known to be affected.

@backstage plugin-auth-backend≤ < 0.27.1enisa_euvdEU
linuxfoundation backstage≤ 0.27.0nvdUScpe:2.3:a:linuxfoundation:backstage:*:*:*:*:*:*:*:*
npm @backstage/plugin-auth-backend< 0.27.1osvUSpkg:npm/%40backstage/plugin-auth-backend

advisories (1)

Vendor and ecosystem advisories describing this.

GHSA-wqvh-63mv-9w92@backstage/plugin-auth-backend: OAuth redirect URI allowlist bypass2026-03-12ghsa · osvUS
### Impact The experimental OIDC provider in `@backstage/plugin-auth-backend` is vulnerable to a redirect URI allowlist bypass. Instances that have enabled experimental Dynamic Client Registration or Client ID Metadata Documents and configured `allowedRedirectUriPatterns` are affected. A specially crafted redirect URI can pass the allowlist validation while resolving to an attacker-controlled host. If a victim approves the resulting OAuth consent request, their authorization code is sent to the attacker, who can exchange it for a valid access token. This requires victim interaction and that one of the experimental features is explicitly enabled, which is not the default. ### Patches Upgrade to `@backstage/plugin-auth-backend` version 0.27.1 or later. ### Workarounds Disable experimental Dynamic Client Registration and Client ID Metadata Documents features if they are not required. ### References - [RFC 6749 Section 3.1.2 - Redirection Endpoint](https://datatracker.ietf.org/doc/html/rfc6749#section-3.1.2)

also known as (3)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd nvd osv NVD CVE.org MITRE

published 2026-03-12modified 2026-06-17

references (5)

External citations — patches, advisories, analysis.

scry

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