CVE-2026-55205
Hermes WebUI < 0.51.468 - Resource Exhaustion via Unauthenticated OAuth Flow Endpoint
Description
Hermes WebUI before 0.51.468 contains a resource exhaustion vulnerability in the unauthenticated POST /api/onboarding/oauth/start endpoint that allows unbounded accumulation of in-memory flow state and daemon threads. Attackers can send repeated or concurrent requests to exhaust server memory and thread resources, potentially triggering repeated outbound device-code requests to upstream OAuth providers.
INFO
Published Date :
June 18, 2026, 5:16 p.m.
Last Modified :
June 22, 2026, 6:43 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 | MEDIUM | 83251b91-4cc7-4094-a5c7-464a1b83ea10 | ||||
| CVSS 4.0 | MEDIUM | [email protected] |
Solution
- Update Hermes WebUI to version 0.51.468.
- Monitor resource usage after updating.
- Restrict access to the API endpoint.
- Implement rate limiting on the endpoint.
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-2026-55205.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-55205 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-2026-55205
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-2026-55205 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-55205 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. 18, 2026
Action Type Old Value New Value Added Reference https://github.com/nesquena/hermes-webui/pull/3970 Added SSVC {'id': 'CVE-2026-55205', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'poc'}, {'automatable': 'yes'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-06-18T17:36:03.154710Z'} -
New CVE Received by [email protected]
Jun. 18, 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': '0.51.468', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '0.51.468', 'versionType': 'semver'}], 'packageURL': 'pkg:npm/hermes-webui-devtools', 'defaultStatus': 'unaffected'}] Added Description Hermes WebUI before 0.51.468 contains a resource exhaustion vulnerability in the unauthenticated POST /api/onboarding/oauth/start endpoint that allows unbounded accumulation of in-memory flow state and daemon threads. Attackers can send repeated or concurrent requests to exhaust server memory and thread resources, potentially triggering repeated outbound device-code requests to upstream OAuth providers. Added CVSS V4.0 AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/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:N/UI:N/S:U/C:N/I:N/A:L Added CWE CWE-770 Added Reference https://github.com/nesquena/hermes-webui/commit/ce272d9cd5f8e5a4521278f56eb5388010901646 Added Reference https://github.com/nesquena/hermes-webui/pull/3970 Added Reference https://github.com/nesquena/hermes-webui/pull/4338 Added Reference https://github.com/nesquena/hermes-webui/releases/tag/v0.51.468 Added Reference https://www.vulncheck.com/advisories/hermes-webui-resource-exhaustion-via-unauthenticated-oauth-flow-endpoint