Goal Reached Thanks to every supporter — we hit 100%!

Goal: 1000 CNY · Raised: 1359 CNY

100%

Buy Us a Coffee

CVE-2026-55438— Coder's workspace app CORS origin check can be bypassed via UUID-based subdomain spoofing

Quick assessment

Affected

coder coder

Exploitation

No confirmed in-the-wild exploitation; assess based on exposure

Recommended action

Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Coder是Coder组织开源的一个可以在公共或私有云基础设施中设置开发环境的应用程序。 Coder存在输入验证错误漏洞，该漏洞源于Coder的基于子域名的工作空间app代理允许绕过同源CORS检查。当工作空间名称的子域名段解析为UUID时，工作空间通过ID解析而未确认URL的用户名与真实所有者匹配，而CORS中间件信任主机名中未验证的用户名。以下版本受到影响：2.29.17之前版本、2.30.0版本至2.32.7之前版本、2.33.0版本至2.33.8之前版本和2.34.0版本至2.34.2之前版本。

CVSS 5.8 · Medium EPSS 0.22% · P13 Updated Jul 09, 2026

Possible ATT&CK Techniques 1 AI

T1556 · Modify Authentication Process

Affected Version Matrix 4

Vendor	Product	Version Range	Status
coder	coder	`>= 2.34.0, < 2.34.2`	affected
		`>= 2.33.0, < 2.33.8`	affected
		`>= 2.30.0, < 2.32.7`	affected
		`< 2.29.17`	affected

Get alerts for future matching vulnerabilities Log in to subscribe

I. Basic Information for CVE-2026-55438

Vulnerability Information

Have questions about the vulnerability? See if Shenlong's analysis helps!

View Shenlong Deep Dive ↗

Although we use advanced large model technology, its output may still contain inaccurate or outdated information.Shenlong tries to ensure data accuracy, but please verify and judge based on the actual situation.

Vulnerability Title

Coder's workspace app CORS origin check can be bypassed via UUID-based subdomain spoofing

Source: CVE Program / CVE List V5

Vulnerability Description

Coder allows organizations to provision remote development environments via Terraform. Prior to versions 2.29.17, 2.32.7, 2.33.8, and 2.34.2, Coder's subdomain-based workspace app proxy allowed the same-owner CORS check to be bypassed. When a workspace-name subdomain segment parsed as a UUID, the workspace was resolved by ID without confirming the URL's username matched the real owner, while the CORS middleware trusted the unverified username in the hostname. Practical exploitation requires subdomain app routing (wildcard hostname) enabled and a victim who visits the attacker's crafted app URL while authenticated. The fix in versions 2.29.17, 2.32.7, 2.33.8, and 2.34.2 validates the subdomain username against the resolved workspace's actual owner and bases the same-owner CORS decision on the authoritative owner identity. No known workarounds are available.

Source: CVE Program / CVE List V5

CVSS Information

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

Source: CVE Program / CVE List V5

Vulnerability Type

源验证错误

Source: CVE Program / CVE List V5

Vulnerability Title

Coder 输入验证错误漏洞

Source: CNNVD (China National Vulnerability Database)

Vulnerability Description

Source: CNNVD (China National Vulnerability Database)

CVSS Information

N/A

Source: CNNVD (China National Vulnerability Database)

Vulnerability Type

N/A

Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor	Product	Affected Versions	CPE	Subscribe
coder	coder	>= 2.34.0, < 2.34.2	-

II. Public POCs for CVE-2026-55438

#	POC Description	Source Link	Shenlong Link

AI-Generated POC Premium

No public POC found.

III. Intelligence Information for CVE-2026-55438

请登录查看更多情报信息。

Patches & Fixes for CVE-2026-55438 (2)

Vendor Advisories for CVE-2026-55438 (1)

🔗 Workspace app CORS origin check can be bypassed via UUID-based subdomain spoofing · Advisory · coder/coder · GitHub Read full article x_refsource_CONFIRM

Vendor Pages for CVE-2026-55438 (4)

🔗 Release v2.32.7 [SECURITY] · coder/coder · GitHub Read full article x_refsource_MISC
🔗 Release v2.34.2 [SECURITY] · coder/coder · GitHub Read full article x_refsource_MISC
🔗 Release v2.33.8 [SECURITY] · coder/coder · GitHub Read full article x_refsource_MISC
🔗 Release v2.29.17 [SECURITY] · coder/coder · GitHub Read full article x_refsource_MISC

https://www.cve.org/CVERecord?id=CVE-2026-55438

Same Patch Batch · coder · 2026-07-08 · 8 CVEs total

CVE-2026-55429	8.7 HIGH	Coder's workspace app upsert allows cross-workspace agent rebinding via user-controlled ap
CVE-2026-55431	7.7 HIGH	Coder's session token leaked to arbitrary hosts via `coder open app` for external workspac
CVE-2026-55436	7.4 HIGH	Coder's AI Bridge Proxy skips TLS certificate verification in default configuration
CVE-2026-55430	5.8 MEDIUM	Coder's subdomain workspace app routing trusts unauthenticated X-Forwarded-Host header, en
CVE-2026-55437	5.4 MEDIUM	Coder vulnerable to stored HTML injection via workspace agent logs in AgentLogLine compone
CVE-2026-55432	5.4 MEDIUM	Coder's sub-agent app registration bypasses template port-sharing policy enforcement
CVE-2026-55433	5.4 MEDIUM	Coder: Devcontainer recreate endpoint missing write authorization allows read-only roles t

IV. Related Vulnerabilities

Same product: coder

Same vendor: coder

Same weakness: CWE-346