CVE-2025-47269Network attack vector

Session hijacking via unvalidated proxy port

Published May 9, 2025 · Updated May 10, 2025

Confused-deputy behavior in Coder code-server before 4.99.4 allows remote attackers to steal session cookies through a crafted proxy URL. The path proxy's getProxyTarget function inserts req.params.port into a URL authority without numeric validation, so an at-sign redirects the request and its cookies to an attacker-controlled domain. Exploitation requires the built-in proxy and an authenticated user to follow the link; the stolen cookie grants access to the host as the code-server service user.

CVSS severity8.3
High
EPSS probability42.69%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Confused-deputy behavior in Coder code-server before 4.99.4 allows remote attackers to steal session cookies through a crafted proxy URL. The path proxy's getProxyTarget function inserts req.params.port into a URL authority without numeric validation, so an at-sign redirects the request and its cookies to an attacker-controlled domain. Exploitation requires the built-in proxy and an authenticated user to follow the link; the stolen cookie grants access to the host as the code-server service user.

The record

CVE
CVE-2025-47269
Published
May 9, 2025
Updated
May 10, 2025
Vendor
Coder
Product
code-server
Classifications
CWE-441, T1539
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 9, 2025CVE publishedPublication date reported by the CVE source.
  2. May 10, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 4.99.4

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Coder · code-serverversion=< 4.99.4

Published CVSS scores

8.3GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-441Unintended Proxy or Intermediary ('Confused Deputy')
T1539Steal Web Session Cookie

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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