CVE-2023-26114Network attack vector

Session hijacking via unchecked WebSocket Origin

Published Mar 23, 2023 · Updated Feb 25, 2025

Missing WebSocket Origin validation in Coder code-server before 4.10.1 allows remote attackers to access data through a victim's session. The WebSocket routes accept cross-origin handshakes without comparing the Origin header with Host or forwarded-host values, letting a hostile page reuse the victim's session. Exploitation requires a logged-in victim to visit attacker-controlled content and is limited to that victim's privileges; older browsers without SameSite cookie support and shared-root subdomains are exposed.

CVSS severity9.3
Critical
EPSS probability0.34%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Missing WebSocket Origin validation in Coder code-server before 4.10.1 allows remote attackers to access data through a victim's session. The WebSocket routes accept cross-origin handshakes without comparing the Origin header with Host or forwarded-host values, letting a hostile page reuse the victim's session. Exploitation requires a logged-in victim to visit attacker-controlled content and is limited to that victim's privileges; older browsers without SameSite cookie support and shared-root subdomains are exposed.

The record

CVE
CVE-2023-26114
Published
Mar 23, 2023
Updated
Feb 25, 2025
Vendor
Coder
Product
code-server
Classifications
CWE-1385, CWE-346, T1189
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 23, 2023CVE publishedPublication date reported by the CVE source.
  2. Feb 25, 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=0 <4.10.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Coder · code-serverversion=0 <4.10.1

Published CVSS scores

9.3GitHub Advisory DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N

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-1385Missing Origin Validation in WebSockets
CWE-346Origin Validation Error
T1189Drive-by Compromise

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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