CVE Watch19 sept 2026

CVE-2026-89058

A flaw was found in RESTEasy's CorsFilter, which, when configured to allow all origins ("*"), reflects the request's Origin header back in t

CVSS

7.4

Alto

EPSS

0.4%

p36

KEV

—

Exploit Today

0-100

Publicado: 18 sept 2026 · Última mod.: 19 sept 2026 · CWE-942

EPSS · 30d

0.3%EPSS · 30 días0.4%

2026-09-182026-09-22

Descripción técnica

A flaw was found in RESTEasy's CorsFilter, which, when configured to allow all origins ("*"), reflects the request's Origin header back in the Access-Control-Allow-Origin response together with Access-Control-Allow-Credentials: true. This permissive cross-origin policy allows a malicious website to make credentialed cross-origin requests and read authenticated responses from a victim's session, resulting in a loss of confidentiality.

Referencias oficiales

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CVE-2026-90882—

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——0The open-vsx.org deployment returned Access-Control-Allow-Origin reflecting the requesting origin together with Access-Control-Allow-Credentials: true on the authenticated /user/ endpoints. A page on any origin could therefore issue credentialed requests to the service in a logged-in user's browser and read the responses. This exposed /user (login name, avatar, homepage, tokens URL), /user/tokens, /user/namespaces, /user/extensions, /user/search/{name} and /user/namespace/{name}/members, and — because /user/csrf was readable the same way — allowed the CSRF protection on write endpoints to be defeated. Chaining the two, an attacker page could call /user/token/create and exfiltrate a personal access token carrying publish and delete rights over the victim's namespaces. The headers were emitted by the CDN/edge layer, not by the application: the Open VSX software sets allowCredentials(true) in exactly one place, against a single exact origin derived from ovsx.webui.url, and defines no CORS mapping on /user/ beyond it. No configuration of the software produces origin reflection with credentials.1h CVE-2026-565953.1 BAJ

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——1HCL BigFix Service Management is affected by a CORS Misconfiguration vulnerability due to improperly validated origin headers, which could allow an attacker to craft a malicious web page that interacts with the vulnerable application, enabling unauthorized access to protected resources and restricted APIs on behalf of a victim.4d CVE-2026-923593.1 BAJ

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——4A security flaw has been discovered in ag-ui-protocol ag-ui 0.3.0. The affected element is the function create_strands_app of the file integrations/aws-strands/python/src/ag_ui_strands/utils.py of the component CORSMiddleware. The manipulation results in permissive cross-domain policy with untrusted domains. The attack may be launched remotely. The attack requires a high level of complexity. The exploitability is described as difficult. Upgrading to version AGUI.Abstractions@0.0.6 is sufficient to fix this issue. The patch is identified as 9b143b9668fa52c2054ede9d34a45ac4b4401089. It is suggested to upgrade the affected component.6d CVE-2026-824388.1 ALT

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——3Description Three separate mechanisms allowed a web page on an unrelated origin to read responses that Storm's HTTP components served to an authenticated user. The Logviewer reflected the request's `Origin` header back in `Access-Control-Allow-Origin` while also sending `Access-Control-Allow-Credentials: true`. The published security model documents a permissive `Access-Control-Allow-Origin: *` posture as accepted, which is safe precisely because browsers refuse to honour `*` together with credentials; reflecting the concrete origin removes that protection. The shared CORS filter used by the UI, the Logviewer and DRPC was configured with a response header name where an initialisation parameter name was expected. The container ignored the setting and applied its own defaults, which allow credentials. Finally, the UI and Logviewer wrapped API responses in a caller-supplied JSONP callback for every GET request. A script element on any origin can load such a response, which bypasses the same-origin policy entirely rather than negotiating it, and there was no way to turn the behaviour off. In each case the effect is that a page visited by an authenticated operator can read cluster, topology and log data on their behalf. Mitigation Upgrade to 3.1.0, where the Logviewer no longer reflects the request origin in a credentialed response, the CORS filter is configured explicitly, and JSONP wrapping is governed by `ui.enable.jsonp`, which defaults to false. Note that disabling JSONP is a behaviour change for tooling that passes a `callback` query parameter; such tooling should be moved to ordinary JSON requests. Users who cannot upgrade immediately should place the UI, Logviewer and DRPC HTTP endpoints behind a reverse proxy that strips `Access-Control-Allow-Origin` and `Access-Control-Allow-Credentials` from responses and rejects requests carrying a `callback` parameter. Credit The ASF -- found using Claude agents to study the security of open-source projects, validated and reported by Apache Storm.8d CVE-2026-628958.8 ALT

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