Cross-profile transcript disclosure via unscoped session lookup
Published Jun 17, 2026 · Updated Jun 17, 2026
Broken access control in Hermes WebUI before 0.51.443 allows remote authenticated users to read cross-profile session transcripts. The GET /api/session handler loads a session by its caller-supplied ID and returns messages and metadata without verifying that its profile matches the active profile. Exploitation requires a multi-profile deployment and a known, leaked, or guessed foreign session ID; the demonstrated impact is disclosure of that profile's conversation data.
Summary
What happened
Broken access control in Hermes WebUI before 0.51.443 allows remote authenticated users to read cross-profile session transcripts. The GET /api/session handler loads a session by its caller-supplied ID and returns messages and metadata without verifying that its profile matches the active profile. Exploitation requires a multi-profile deployment and a known, leaked, or guessed foreign session ID; the demonstrated impact is disclosure of that profile's conversation data.
The record
- CVE
- CVE-2026-55197
- Published
- Jun 17, 2026
- Updated
- Jun 17, 2026
- Vendor
- Nathan Esquenazi
- Product
- Hermes WebUI
- Classifications
- CWE-639, T1213
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Jun 17, 2026CVE publishedPublication date reported by the CVE source.
- Jun 17, 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=0 <0.51.443
What conditions does exploitation require?
What is affected?
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
- Cross-profile session transcript proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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