CWE-441
Allowed-with-ReviewUnintended Proxy or Intermediary ('Confused Deputy')
Abstraction: Class · Status: Draft
The product receives a request, message, or directive from an upstream component, but the product does not sufficiently preserve the original source of the request before forwarding the request to an external actor that is outside of the product's control sphere. This causes the product to appear to be the source of the request, leading it to act as a proxy or other intermediary between the upstream component and the external actor.
164 vulnerabilities reference this CWE, most recent first.
GHSA-W34F-VM33-HPXX
Vulnerability from github – Published: 2026-03-02 21:31 – Updated: 2026-03-03 00:31In multiple locations, there is a possible privilege escalation due to a confused deputy. This could lead to local escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation.
{
"affected": [],
"aliases": [
"CVE-2026-0008"
],
"database_specific": {
"cwe_ids": [
"CWE-441"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-03-02T19:16:29Z",
"severity": "HIGH"
},
"details": "In multiple locations, there is a possible privilege escalation due to a confused deputy. This could lead to local escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation.",
"id": "GHSA-w34f-vm33-hpxx",
"modified": "2026-03-03T00:31:10Z",
"published": "2026-03-02T21:31:31Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-0008"
},
{
"type": "WEB",
"url": "https://source.android.com/security/bulletin/2026-03-01"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
GHSA-WG33-5H85-7Q5P
Vulnerability from github – Published: 2025-02-06 17:07 – Updated: 2025-02-06 19:54Impact
In mitmweb 11.1.0 and below, a malicious client can use mitmweb's proxy server (bound to *:8080 by default) to access mitmweb's internal API (bound to 127.0.0.1:8081 by default). In other words, while the client cannot access the API directly (good), they can access the API through the proxy (bad). An attacker may be able to escalate this SSRF-style access to remote code execution.
The mitmproxy and mitmdump tools are unaffected. Only mitmweb is affected. The block_global option, which is enabled by default, blocks connections originating from publicly-routable IP addresses in the proxy. The attacker needs to be in the same local network.
Patches
The vulnerability has been fixed in mitmproxy 11.1.2 and above.
Acknowledgements
We thank Stefan Grönke (@gronke) for reporting this vulnerability as part of a security audit by Radically Open Security. This audit was supported by the NGI0 Entrust fund established by NLnet.
Timeline
- 2025-01-14: Received initial report.
- 2025-01-14: Verified report and confirmed receipt.
- 2025-01-19: Shared patch with researcher.
- 2025-02-04: Received final confirmation that patch is working.
- 2025-02-05: Published patched release and advisory.
{
"affected": [
{
"package": {
"ecosystem": "PyPI",
"name": "mitmproxy"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "11.1.2"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2025-23217"
],
"database_specific": {
"cwe_ids": [
"CWE-288",
"CWE-441"
],
"github_reviewed": true,
"github_reviewed_at": "2025-02-06T17:07:41Z",
"nvd_published_at": "2025-02-06T18:15:32Z",
"severity": "HIGH"
},
"details": "### Impact\nIn mitmweb 11.1.0 and below, a malicious client can use mitmweb\u0027s proxy server (bound to `*:8080` by default) to access mitmweb\u0027s internal API (bound to `127.0.0.1:8081` by default). In other words, while the client cannot access the API directly (good), they can access the API through the proxy (bad). An attacker may be able to escalate this [SSRF](https://en.wikipedia.org/wiki/Server-side_request_forgery)-style access to remote code execution.\n\nThe mitmproxy and mitmdump tools are unaffected. Only mitmweb is affected. The `block_global` option, which is enabled by default, blocks connections originating from publicly-routable IP addresses in the proxy. The attacker needs to be in the same local network.\n\n### Patches\n\nThe vulnerability has been fixed in mitmproxy 11.1.2 and above.\n\n### Acknowledgements\n\nWe thank Stefan Gr\u00f6nke (@gronke) for reporting this vulnerability as part of a security audit by [Radically Open Security](https://www.radicallyopensecurity.com/). This audit was supported by the [NGI0 Entrust fund](https://nlnet.nl/entrust/) established by [NLnet](https://nlnet.nl/).\n\n### Timeline\n\n- **2025-01-14**: Received initial report. \n- **2025-01-14**: Verified report and confirmed receipt.\n- **2025-01-19**: Shared patch with researcher.\n- **2025-02-04**: Received final confirmation that patch is working.\n- **2025-02-05**: Published patched release and advisory.",
"id": "GHSA-wg33-5h85-7q5p",
"modified": "2025-02-06T19:54:56Z",
"published": "2025-02-06T17:07:41Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/mitmproxy/mitmproxy/security/advisories/GHSA-wg33-5h85-7q5p"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-23217"
},
{
"type": "WEB",
"url": "https://github.com/mitmproxy/mitmproxy/commit/fa89055e196d953f11fd241e36ee37858993486a"
},
{
"type": "WEB",
"url": "https://en.wikipedia.org/wiki/Server-side_request_forgery"
},
{
"type": "PACKAGE",
"url": "https://github.com/mitmproxy/mitmproxy"
},
{
"type": "WEB",
"url": "https://github.com/mitmproxy/mitmproxy/blob/main/CHANGELOG.md"
},
{
"type": "WEB",
"url": "https://github.com/mitmproxy/mitmproxy/blob/main/CHANGELOG.md#06-february-2025-mitmproxy-1112"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N",
"type": "CVSS_V4"
}
],
"summary": "Mitmweb API Authentication Bypass Using Proxy Server"
}
GHSA-X27W-589X-FRM2
Vulnerability from github – Published: 2026-07-20 23:25 – Updated: 2026-07-20 23:25Summary
When ISR is enabled, the serverless entrypoint lets an unauthenticated request
decide which route the origin renders. The internal _isr function reads the
x_astro_path query parameter and rewrites the request path to it without any
authentication. Edge level access controls only ever see the /_isr path, so
they do not apply to the route that actually gets rendered. This is the same
confused deputy problem as CVE-2026-33768, reachable again through the ISR path.
Impact
This affects apps that use @astrojs/vercel with isr: true and protect routes
at the edge. Two common setups are affected:
- Path rules or firewall deny rules configured on Vercel (for example blocking
/admin). - Split deployments (
edgeMiddleware: true) where authorization lives in Astro middleware, since that middleware runs at the edge and not in the origin.
An attacker reads any GET rendered route by requesting
/_isr?x_astro_path=/the/protected/path. No credentials are required. The
protected content is produced by a fresh origin render, so the attack does not
depend on the response being cached first.
Details
packages/integrations/vercel/src/serverless/entrypoint.ts picks the real path
like this:
if (hasValidMiddlewareSecret) {
realPath = request.headers.get(ASTRO_PATH_HEADER); // secret checked
} else if (request.headers.get('x-vercel-isr') === '1') {
realPath = url.searchParams.get(ASTRO_PATH_PARAM); // no secret checked
}
The header path is gated by the per build secret and is fine. The ISR branch is not. Two facts make it reachable by anyone:
- The
_isrfunction is publicly addressable. - Vercel sets
x-vercel-isr: 1on requests to it, including direct external requests, so the attacker does not even need to send that header.
So GET /_isr?x_astro_path=/admin sets the internal path to /admin and renders
it. The edge saw only /_isr, which is allowed, so any path based rule on
/admin never fires. In split deployments the edge middleware also runs against
/_isr, and the origin does not run middleware at all, so middleware based auth
is skipped as well.
How this regressed
CVE-2026-33768 was fixed in 10.0.2 by commit 335a204161 (PR #15959), which
required the secret for every path override and removed the query parameter
source. Commit aa266364fe (PR #16079, "Fix ISR path rewrite to prevent 404")
brought the query parameter back, guarded only by the x-vercel-isr header. That
header is not a security boundary, so the fix was effectively undone for ISR
routes starting in 10.0.3.
Worth noting the contrast: the original report treated Edge Middleware as the
mitigation and scoped the issue to deployments without it. Here, for split
deployments, Edge Middleware is bypassed too, since the attacker reaches /_isr
directly and the middleware only sees /_isr while the origin runs none.
Proof of concept
- Create an Astro app with
output: 'server'and adaptervercel({ isr: true }). - Add a page at
/adminthat returns sensitive content. - Deny
/adminat the edge, for example a Vercel path rule that returns 403, or a middleware auth check in a split (edgeMiddleware: true) build. - Request
/admin. It is blocked (403). - Request
/_isr?x_astro_path=/admin. It returns 200 with the admin content. The response headerX-Vercel-Cache: MISSconfirms it was rendered fresh, not served from an existing cache entry.
What is not affected
- Classic (non split) middleware. It runs inside the origin against the rewritten path, so it still applies to the target route.
- State changing requests. Vercel serves ISR functions for GET only, and returns 403 for POST, PUT and DELETE, so the method preserving variant of CVE-2026-33768 does not reproduce here. Impact is limited to reading (confidentiality).
- Whole deployment protection (Vercel SSO or password), which also covers
/_isr.
Severity
Unauthenticated read of any GET rendered route that is protected only at the edge. No integrity or availability impact because the vector is GET only.
Suggested fix
One option would be to require the secret again for path overrides, the way
PR #15959 did, so the ISR branch stops trusting the client supplied x_astro_path.
The 404 that PR #16079 was fixing would then need another approach that does not
rely on client input.
{
"affected": [
{
"package": {
"ecosystem": "npm",
"name": "@astrojs/vercel"
},
"ranges": [
{
"events": [
{
"introduced": "10.0.3"
},
{
"fixed": "11.0.3"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [],
"database_specific": {
"cwe_ids": [
"CWE-441",
"CWE-862"
],
"github_reviewed": true,
"github_reviewed_at": "2026-07-20T23:25:07Z",
"nvd_published_at": null,
"severity": "MODERATE"
},
"details": "## Summary\nWhen ISR is enabled, the serverless entrypoint lets an unauthenticated request\ndecide which route the origin renders. The internal `_isr` function reads the\n`x_astro_path` query parameter and rewrites the request path to it without any\nauthentication. Edge level access controls only ever see the `/_isr` path, so\nthey do not apply to the route that actually gets rendered. This is the same\nconfused deputy problem as CVE-2026-33768, reachable again through the ISR path.\n\n## Impact\nThis affects apps that use `@astrojs/vercel` with `isr: true` and protect routes\nat the edge. Two common setups are affected:\n\n1. Path rules or firewall deny rules configured on Vercel (for example blocking\n `/admin`).\n2. Split deployments (`edgeMiddleware: true`) where authorization lives in Astro\n middleware, since that middleware runs at the edge and not in the origin.\n\nAn attacker reads any GET rendered route by requesting\n`/_isr?x_astro_path=/the/protected/path`. No credentials are required. The\nprotected content is produced by a fresh origin render, so the attack does not\ndepend on the response being cached first.\n\n## Details\n`packages/integrations/vercel/src/serverless/entrypoint.ts` picks the real path\nlike this:\n\n```js\nif (hasValidMiddlewareSecret) {\n realPath = request.headers.get(ASTRO_PATH_HEADER); // secret checked\n} else if (request.headers.get(\u0027x-vercel-isr\u0027) === \u00271\u0027) {\n realPath = url.searchParams.get(ASTRO_PATH_PARAM); // no secret checked\n}\n```\n\nThe header path is gated by the per build secret and is fine. The ISR branch is\nnot. Two facts make it reachable by anyone:\n\n1. The `_isr` function is publicly addressable.\n2. Vercel sets `x-vercel-isr: 1` on requests to it, including direct external\n requests, so the attacker does not even need to send that header.\n\nSo `GET /_isr?x_astro_path=/admin` sets the internal path to `/admin` and renders\nit. The edge saw only `/_isr`, which is allowed, so any path based rule on\n`/admin` never fires. In split deployments the edge middleware also runs against\n`/_isr`, and the origin does not run middleware at all, so middleware based auth\nis skipped as well.\n\n## How this regressed\nCVE-2026-33768 was fixed in 10.0.2 by commit 335a204161 (PR #15959), which\nrequired the secret for every path override and removed the query parameter\nsource. Commit aa266364fe (PR #16079, \"Fix ISR path rewrite to prevent 404\")\nbrought the query parameter back, guarded only by the `x-vercel-isr` header. That\nheader is not a security boundary, so the fix was effectively undone for ISR\nroutes starting in 10.0.3.\n\nWorth noting the contrast: the original report treated Edge Middleware as the\nmitigation and scoped the issue to deployments without it. Here, for split\ndeployments, Edge Middleware is bypassed too, since the attacker reaches `/_isr`\ndirectly and the middleware only sees `/_isr` while the origin runs none.\n\n## Proof of concept\n1. Create an Astro app with `output: \u0027server\u0027` and adapter\n `vercel({ isr: true })`.\n2. Add a page at `/admin` that returns sensitive content.\n3. Deny `/admin` at the edge, for example a Vercel path rule that returns 403, or\n a middleware auth check in a split (`edgeMiddleware: true`) build.\n4. Request `/admin`. It is blocked (403).\n5. Request `/_isr?x_astro_path=/admin`. It returns 200 with the admin content.\n The response header `X-Vercel-Cache: MISS` confirms it was rendered fresh, not\n served from an existing cache entry.\n\n## What is not affected\n1. Classic (non split) middleware. It runs inside the origin against the rewritten\n path, so it still applies to the target route.\n2. State changing requests. Vercel serves ISR functions for GET only, and returns\n 403 for POST, PUT and DELETE, so the method preserving variant of CVE-2026-33768\n does not reproduce here. Impact is limited to reading (confidentiality).\n3. Whole deployment protection (Vercel SSO or password), which also covers `/_isr`.\n\n## Severity\nUnauthenticated read of any GET rendered route that is protected only at the edge.\nNo integrity or availability impact because the vector is GET only.\n\n## Suggested fix\nOne option would be to require the secret again for path overrides, the way\nPR #15959 did, so the ISR branch stops trusting the client supplied `x_astro_path`.\nThe 404 that PR #16079 was fixing would then need another approach that does not\nrely on client input.",
"id": "GHSA-x27w-589x-frm2",
"modified": "2026-07-20T23:25:07Z",
"published": "2026-07-20T23:25:07Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/withastro/astro/security/advisories/GHSA-mr6q-rp88-fx84"
},
{
"type": "WEB",
"url": "https://github.com/withastro/astro/security/advisories/GHSA-x27w-589x-frm2"
},
{
"type": "WEB",
"url": "https://github.com/withastro/astro/pull/16079"
},
{
"type": "WEB",
"url": "https://github.com/withastro/astro/pull/17370"
},
{
"type": "WEB",
"url": "https://github.com/withastro/astro/commit/3a43cf0f3690a8e33cb30109bc5165611cf38fcd"
},
{
"type": "WEB",
"url": "https://github.com/withastro/astro/commit/aa266364fe9e105317b66e218fe04567307fb57f"
},
{
"type": "PACKAGE",
"url": "https://github.com/withastro/astro"
},
{
"type": "WEB",
"url": "https://github.com/withastro/astro/releases/tag/@astrojs/vercel@11.0.3"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N",
"type": "CVSS_V4"
}
],
"summary": "Astro: Unauthenticated path override in the @astrojs/vercel ISR function"
}
GHSA-XJV7-6W92-42R7
Vulnerability from github – Published: 2025-10-01 21:20 – Updated: 2025-11-20 17:20Summary
The /mpl/<port>/<route> endpoint, which is accessible without authentication on default Marimo installations allows for external attackers to reach internal services and arbitrary ports.
Details
From our understanding, this route is used internally to provide access to interactive matplotlib visualizations.
marimo/marimo/_server/main.py at main · marimo-team/marimo
This endpoint functions as an unauthenticated proxy, allowing an attacker to connect to any service running on the local machine via the specified <port> and <route>.
The existence of this proxy is visible in the application's code (marimo/_server/main.py), but there's no official documentation or warning about its behavior or potential risks.
Impact
CWE-441: Proxying Without Authentication
This vulnerability, as it can be used to bypass firewalls and access internal services that are intended to be local-only. The level of impact depends entirely on what services are running and accessible on the local machine.
Full Local Access: An attacker can use this proxy to connect to local services that answer to web sockets, HTTP or ASGI protocol, effectively gaining a foothold on the machine. Depending on the service, this can lead to remote code execution, data exfiltration, or further network penetration.
Exposure of Sensitive Services: Our scans of public-facing Marimo servers have shown that many are exposing sensitive internal services, including:
Old CUPS Servers: Could allow an attacker to view print jobs or configuration or depending on old vulnerabilities, allow RCE.
phpMyAdmin: Provides a web interface to a MySQL database, potentially exposing sensitive data.
RPCMapper: Can be used for network reconnaissance and enumerating services.
While you’d hope people wouldn’t expose marimo instances to the internet, we found numerous public Marimo instances using tools like Shodan. Many of these servers, some even hosted on cloud platforms like AWS GovCloud, were found to be vulnerable. This means the vulnerability isn't limited to a few isolated cases but is a widespread issue affecting production environments.
===
Notes, this was discovered by devgi. I (acepace) followed up and also created this report.
{
"affected": [
{
"package": {
"ecosystem": "PyPI",
"name": "marimo"
},
"ranges": [
{
"events": [
{
"introduced": "0.9.20"
},
{
"fixed": "0.16.4"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [],
"database_specific": {
"cwe_ids": [
"CWE-441"
],
"github_reviewed": true,
"github_reviewed_at": "2025-10-01T21:20:11Z",
"nvd_published_at": null,
"severity": "MODERATE"
},
"details": "### Summary\nThe `/mpl/\u003cport\u003e/\u003croute\u003e` endpoint, which is accessible without authentication on default Marimo installations allows for external attackers to reach internal services and arbitrary ports. \n\n### Details\nFrom our understanding, this route is used internally to provide access to interactive matplotlib visualizations.\n[marimo/marimo/_server/main.py at main \u00b7 marimo-team/marimo](https://github.com/marimo-team/marimo/blob/main/marimo/_server/main.py) \nThis endpoint functions as an unauthenticated proxy, allowing an attacker to connect to any service running on the local machine via the specified `\u003cport\u003e` and `\u003croute\u003e`.\n\nThe existence of this proxy is visible in the application\u0027s code (marimo/_server/main.py), but there\u0027s no official documentation or warning about its behavior or potential risks.\n\n\n### Impact\nCWE-441: Proxying Without Authentication\n\nThis vulnerability, as it can be used to bypass firewalls and access internal services that are intended to be local-only. The level of impact depends entirely on what services are running and accessible on the local machine.\n\nFull Local Access: An attacker can use this proxy to connect to local services that answer to web sockets, HTTP or ASGI protocol, effectively gaining a foothold on the machine. Depending on the service, this can lead to remote code execution, data exfiltration, or further network penetration.\n\nExposure of Sensitive Services: Our scans of public-facing Marimo servers have shown that many are exposing sensitive internal services, including:\n\nOld CUPS Servers: Could allow an attacker to view print jobs or configuration or depending on old vulnerabilities, allow RCE.\n\nphpMyAdmin: Provides a web interface to a MySQL database, potentially exposing sensitive data.\n\nRPCMapper: Can be used for network reconnaissance and enumerating services.\n\nWhile you\u2019d hope people wouldn\u2019t expose marimo instances to the internet, we found numerous public Marimo instances using tools like Shodan. Many of these servers, some even hosted on cloud platforms like AWS GovCloud, were found to be vulnerable. This means the vulnerability isn\u0027t limited to a few isolated cases but is a widespread issue affecting production environments.\n\n===\n\nNotes, this was discovered by [devgi](https://github.com/devgi). I ([acepace](https://github.com/acepace)) followed up and also created this report.",
"id": "GHSA-xjv7-6w92-42r7",
"modified": "2025-11-20T17:20:23Z",
"published": "2025-10-01T21:20:11Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/marimo-team/marimo/security/advisories/GHSA-xjv7-6w92-42r7"
},
{
"type": "WEB",
"url": "https://github.com/marimo-team/marimo/commit/0312706d5e594acdb405209b2c8d87c98f46b22b"
},
{
"type": "PACKAGE",
"url": "https://github.com/marimo-team/marimo"
},
{
"type": "WEB",
"url": "https://github.com/marimo-team/marimo/releases/tag/0.16.4"
},
{
"type": "WEB",
"url": "https://marimo-team.notion.site/cve-proxy-without-authentication"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N",
"type": "CVSS_V4"
}
],
"summary": "marimo vulnerable to proxy abuse of /mpl/{port}/"
}
Mitigation
Enforce the use of strong mutual authentication mechanism between the two parties.
Mitigation
Whenever a product is an intermediary or proxy for transactions between two other components, the proxy core should not drop the identity of the initiator of the transaction. The immutability of the identity of the initiator must be maintained and should be forwarded all the way to the target.
CAPEC-219: XML Routing Detour Attacks
An attacker subverts an intermediate system used to process XML content and forces the intermediate to modify and/or re-route the processing of the content. XML Routing Detour Attacks are Adversary in the Middle type attacks (CAPEC-94). The attacker compromises or inserts an intermediate system in the processing of the XML message. For example, WS-Routing can be used to specify a series of nodes or intermediaries through which content is passed. If any of the intermediate nodes in this route are compromised by an attacker they could be used for a routing detour attack. From the compromised system the attacker is able to route the XML process to other nodes of their choice and modify the responses so that the normal chain of processing is unaware of the interception. This system can forward the message to an outside entity and hide the forwarding and processing from the legitimate processing systems by altering the header information.
CAPEC-465: Transparent Proxy Abuse
A transparent proxy serves as an intermediate between the client and the internet at large. It intercepts all requests originating from the client and forwards them to the correct location. The proxy also intercepts all responses to the client and forwards these to the client. All of this is done in a manner transparent to the client.