CVE-2026-55197

MEDIUM

Hermes WebUI < 0.51.443 - Broken Access Control in /api/session Endpoint

Title source: cna
STIX 2.1

Description

Hermes WebUI before 0.51.443 contains a broken access control vulnerability in the /api/session endpoint that allows authenticated users to disclose cross-profile session transcripts. Attackers can bypass profile boundary checks by directly querying session IDs belonging to other profiles via GET /api/session?session_id=<foreign_id>&messages=1 to retrieve unauthorized conversation transcripts and metadata.

References (5)

Core 5
Core References
Release Notes release-notes
Release Notes
https://github.com/nesquena/hermes-webui/releases/tag/v0.51.443
Technical Description technical-description
Researcher Pull Request
https://github.com/nesquena/hermes-webui/pull/3982
Issue Tracking issue-tracking
Maintainer Pull Request
https://github.com/nesquena/hermes-webui/pull/4269

Scores

CVSS v3 6.5
EPSS 0.0027
EPSS Percentile 18.8%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

CISA SSVC

Vulnrichment
Exploitation poc
Automatable no
Technical Impact partial

Details

CWE
CWE-639
Status published
Products (2)
nesquena/hermes-webui < 0.51.443
nesquena/hermes-webui 0.51.443
Published Jun 17, 2026
Tracked Since Jun 18, 2026