No access to your tenant or devices. Every item links to its source. What this means
code-server runs VS Code on any machine anywhere through browser access. Prior to version 4.99.4, a maliciously crafted URL using the proxy subpath can result in the attacker gaining access to the session token. Failure to properly validate the port for a proxy request can result in proxying to an arbitrary domain. The malicious URL `https://<code-server>/proxy/[email protected]/path` would be proxied to `[email protected]/path` where the attacker could exfiltrate a user's session token. Any user who runs code-server with the built-in proxy enabled and clicks on maliciously crafted links that go to their code-server instances with reference to /proxy. Normally this is used to proxy local ports, however the URL can reference the attacker's domain instead, and the connection is then proxied to that domain, which will include sending cookies. With access to the session cookie, the attacker can then log into code-server and have full access to the machine hosting code-server as the user running code-server. This issue has been patched in version 4.99.4.
Read the publisher's advisorycode-server runs VS Code on any machine anywhere through browser access. Prior to version 4.99.4, a maliciously crafted URL using the proxy subpath can result in the attacker gaining access to the session token. Failure to properly validate the port for a proxy request can result in proxying to an arbitrary domain. The malicious URL `https://<code-server>/proxy/[email protected]/path` would be proxied to `[email protected]/path` where the attacker could exfiltrate a user's session token. Any user who runs code-server with the built-in proxy enabled and clicks on maliciously crafted links that go to their code-server instances with reference to /proxy. Normally this is used to proxy local ports, however the URL can reference the attacker's domain instead, and the connection is then proxied to that domain, which will include sending cookies. With access to the session cookie, the attacker can then log into code-server and have full access to the machine hosting code-server as the user running code-server. This issue has been patched in version 4.99.4.
Read the publisher's advisorycode-server runs VS Code on any machine anywhere through browser access. Prior to version 4.99.4, a maliciously crafted URL using the proxy subpath can result in the attacker gaining access to the session token. Failure to properly validate the port for a proxy request can result in proxying to an arbitrary domain. The malicious URL `https://<code-server>/proxy/[email protected]/path` would be proxied to `[email protected]/path` where the attacker could exfiltrate a user's session token. Any user who runs code-server with the built-in proxy enabled and clicks on maliciously crafted links that go to their code-server instances with reference to /proxy. Normally this is used to proxy local ports, however the URL can reference the attacker's domain instead, and the connection is then proxied to that domain, which will include sending cookies. With access to the session cookie, the attacker can then log into code-server and have full access to the machine hosting code-server as the user running code-server. This issue has been patched in version 4.99.4.
Read the publisher's advisory### Summary A maliciously crafted URL using the `proxy` subpath can result in the attacker gaining access to the session token. ### Details Failure to properly validate the port for a `proxy` request can result in proxying to an arbitrary domain. The malicious URL `https://<code-server>/proxy/[email protected]/path` would be proxied to `[email protected]/path` where the attacker could exfiltrate a user's session token. ### Impact Any user who runs code-server with the built-in proxy enabled and clicks on maliciously crafted links that go to their code-server instances with reference to `/proxy`. Normally this is used to proxy local ports, however the URL can reference the attacker's domain instead, and the connection is then proxied to that domain, which will include sending cookies. With access to the session cookie, the attacker can then log into code-server and have full access to the machine hosting code-server as the user running code-server. ### Patches Patched versions are from [v4.99.4](https://github.com/coder/code-server/releases/tag/v4.99.4) onward.
Read the publisher's advisoryVendor product
Shown as published. These rules are not interpreted as NuGet package version ranges.
{
"vendor": "coder",
"product": "code-server",
"versions": [
{
"version": "< 4.99.4",
"status": "affected"
}
]
}Original source record · Cite this exact observation · Complete original publisher JSON
EUVD source date text has no stated timezone and is retained without inventing a UTC instant. Related bulletin membership is not an alias, common cause or applicability claim. A missing vector with a zero score is treated as unrated. Complete vendor/product and underlying source evidence remains in the original JSON.
datePublished: May 9, 2025, 8:59:01 PM
dateUpdated: May 10, 2025, 1:45:13 AM
No normalized affected-package data is projected for this source revision. The original publisher record may contain additional product and version evidence; this does not establish that a package is unaffected.
Original source record · Cite this exact observation · Complete original publisher JSON
NVD analysis and CPE criteria are source context, not proof that a package or your environment is affected. Complete affected data, logical configurations and SSVC are retained in the original JSON.
Source analysis status: Deferred
Weakness classifications: CWE-441
published: 2025-05-09T21:15:51.263
lastModified: 2026-06-17T09:27:38.423
No normalized affected-package data is projected for this source revision. The original publisher record may contain additional product and version evidence; this does not establish that a package is unaffected.
Original source record · Cite this exact observation · Complete original publisher JSON
npm
SEMVER · introduced 0 → fixed 4.99.4
Original source record · Cite this exact observation · Complete original publisher JSON