Cross-app data access via trusted forwarding header
Published Jul 8, 2026 · Updated Jul 8, 2026
Confused-deputy routing in affected Coder releases allows remote authenticated users to read private workspace app responses. The workspace app proxy uses httpapi.RequestHost(), which prefers an attacker-set X-Forwarded-Host value over the real Host value when selecting the target app. Exploitation requires wildcard subdomain routing, an upstream proxy that preserves the header, and a victim who visits the attacker’s shared app; the browser then attaches the victim’s cookie and exposes only private app responses.
Summary
What happened
Confused-deputy routing in affected Coder releases allows remote authenticated users to read private workspace app responses. The workspace app proxy uses httpapi.RequestHost(), which prefers an attacker-set X-Forwarded-Host value over the real Host value when selecting the target app. Exploitation requires wildcard subdomain routing, an upstream proxy that preserves the header, and a victim who visits the attacker’s shared app; the browser then attaches the victim’s cookie and exposes only private app responses.
The record
- CVE
- CVE-2026-55430
- Published
- Jul 8, 2026
- Updated
- Jul 8, 2026
- Vendor
- Coder
- Product
- Coder
- Classifications
- CWE-441, CWE-345
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Jul 8, 2026CVE publishedPublication date reported by the CVE source.
- Jul 8, 2026Record 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.
- Affected versionversion=< 2.29.17
- Affected versionversion=>= 2.30.0, < 2.32.7
- Affected versionversion=>= 2.33.0, < 2.33.8
- Affected versionversion=>= 2.34.0, < 2.34.2
What conditions does exploitation require?
What is affected?
Published CVSS scores
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.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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