---
id: CVE-2026-55198
title: >-
  Hermes WebUI before 0.51.443 contains an authorization bypass vulnerability in
  the session export endpoint that allows authenticated users to access sessions
  from other profiles
summary: >-
  Hermes WebUI before 0.51.443 contains an authorization bypass vulnerability in
  the session export endpoint that allows authenticated users to access sessions
  from other profiles. The _handle_session_export handler in api/routes.py fails
  …
severity: medium
cvss: 6.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N'
cwe:
  - CWE-639
vendor: nesquena
product: hermes-webui
affected:
  - hermes-webui < 0.51.443
published: '2026-06-17'
updated: '2026-09-17'
sourceUpdated: '2026-09-17T18:16:49.083'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-55198'
references:
  - url: >-
      https://github.com/nesquena/hermes-webui/commit/2a3baa71b81ca92da8ece8616a09f15894beec71
    label: disclosure@vulncheck.com
  - url: 'https://github.com/nesquena/hermes-webui/pull/3991'
    label: disclosure@vulncheck.com
  - url: 'https://github.com/nesquena/hermes-webui/pull/4269'
    label: disclosure@vulncheck.com
  - url: 'https://github.com/nesquena/hermes-webui/releases/tag/v0.51.443'
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/hermes-webui-cross-profile-session-data-exfiltration-via-session-export-endpoint
    label: disclosure@vulncheck.com
  - url: 'https://github.com/nesquena/hermes-webui/pull/3991'
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
tags:
  - nvd
  - cve.org
  - exploit-available
exploitAvailable: true
ssvc:
  exploitation: poc
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-06-17T19:30:06.299958Z'
epss: 0.00474
epssPercentile: 0.38389
ingestedAt: '2026-09-17T18:25:15.970Z'
---

## Overview

Hermes WebUI before 0.51.443 contains an authorization bypass vulnerability in the session export endpoint that allows authenticated users to access sessions from other profiles. The _handle_session_export handler in api/routes.py fails to verify active-profile ownership before serializing session data, enabling attackers to exfiltrate foreign session transcripts by guessing or knowing session identifiers.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.