5.8 MEDIUM
- CVSS version (CVSS): 3.1
- Attack Vector (AV): Network (N)
- Attack Complexity (AC): High (H)
- Privileges Required (PR): Low (L)
- User Interaction (UI): Required (R)
- Scope (S): Changed (C)
- Confidentiality (C): High (H)
- Integrity (I): None (N)
- Availability (A): None (N)
- Modified Attack Vector (MAV): Network (N)
- Modified Attack Complexity (MAC): High (H)
- Modified Privileges Required (MPR): Low (L)
- Modified User Interaction (MUI): Required (R)
- Modified Confidentiality (MC): High (H)
- Modified Scope (MS): Changed (C)
- Modified Integrity (MI): None (N)
- Modified Availability (MA): None (N)
Activity log
- Created & dismissed (max. allowed matches exceeded) suggestion
Coder's workspace app CORS origin check can be bypassed via UUID-based subdomain spoofing
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.
References
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https://github.com/coder/coder/security/advisories/GHSA-5wg6-jmq2-53pw x_refsource_CONFIRM
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https://github.com/coder/coder/pull/26085 x_refsource_MISC
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https://github.com/coder/coder/pull/26086 x_refsource_MISC
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https://github.com/coder/coder/releases/tag/v2.29.17 x_refsource_MISC
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https://github.com/coder/coder/releases/tag/v2.32.7 x_refsource_MISC
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https://github.com/coder/coder/releases/tag/v2.33.8 x_refsource_MISC
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https://github.com/coder/coder/releases/tag/v2.34.2 x_refsource_MISC
Affected products
- ==>= 2.34.0, < 2.34.2
- ==>= 2.30.0, < 2.32.7
- ==>= 2.33.0, < 2.33.8
- ==< 2.29.17