CVE-2026-55197
Hermes WebUI < 0.51.443 - Broken Access Control in /api/session Endpoint
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.
INFO
Published Date :
June 17, 2026, 7:18 p.m.
Last Modified :
June 17, 2026, 8:21 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | MEDIUM | 83251b91-4cc7-4094-a5c7-464a1b83ea10 | ||||
| CVSS 3.1 | MEDIUM | [email protected] | ||||
| CVSS 4.0 | HIGH | 83251b91-4cc7-4094-a5c7-464a1b83ea10 | ||||
| CVSS 4.0 | HIGH | [email protected] |
Solution
- Update Hermes WebUI to version 0.51.443 or later.
- Restrict access to the /api/session endpoint.
- Implement strict profile boundary checks.
- Validate all session ID requests.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-55197.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-55197 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-55197
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-55197 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-55197 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jun. 17, 2026
Action Type Old Value New Value Added Reference https://github.com/nesquena/hermes-webui/pull/3982 Added SSVC {'id': 'CVE-2026-55197', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'poc'}, {'automatable': 'no'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-06-17T18:51:32.010912Z'} -
New CVE Received by [email protected]
Jun. 17, 2026
Action Type Old Value New Value Added Affected [{'repo': 'https://github.com/nesquena/hermes-webui', 'vendor': 'nesquena', 'product': 'hermes-webui', 'versions': [{'status': 'affected', 'version': '0', 'lessThan': '0.51.443', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '0.51.443', 'versionType': 'semver'}], 'packageURL': 'pkg:npm/hermes-webui-devtools', 'defaultStatus': 'unaffected'}] Added 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. Added CVSS V4.0 AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Added CVSS V3.1 AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N Added CWE CWE-639 Added Reference https://github.com/nesquena/hermes-webui/commit/2a3baa71b81ca92da8ece8616a09f15894beec71 Added Reference https://github.com/nesquena/hermes-webui/pull/3982 Added Reference https://github.com/nesquena/hermes-webui/pull/4269 Added Reference https://github.com/nesquena/hermes-webui/releases/tag/v0.51.443 Added Reference https://www.vulncheck.com/advisories/hermes-webui-broken-access-control-in-api-session-endpoint