CVE-2026-49955
Hermes WebUI < 0.51.270 Resource Exhaustion via passkey/options
Description
Hermes WebUI before version 0.51.270 contains a resource exhaustion vulnerability that allows unauthenticated remote attackers to degrade service availability by repeatedly calling the passkey options endpoint without completing assertion. Attackers can send unlimited POST requests to the authentication endpoint, causing unbounded growth of the challenge store file and excessive CPU and disk I/O through repeated JSON file rewrites.
INFO
Published Date :
June 9, 2026, 5:17 p.m.
Last Modified :
July 23, 2026, 8:10 a.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 0.51.270 or later.
- Monitor challenge store file size and I/O.
- Implement rate limiting on the passkey options 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-2026-49955.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-49955 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-2026-49955
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-2026-49955 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-49955 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 Translated by [email protected]
Jul. 23, 2026
Action Type Old Value New Value Added Translation Title: Hermes WebUI de nesquena, Description: Hermes WebUI antes de la versión 0.51.270 contiene una vulnerabilidad de agotamiento de recursos que permite a atacantes remotos no autenticados degradar la disponibilidad del servicio llamando repetidamente al endpoint de opciones de clave de acceso sin completar la aserción. Los atacantes pueden enviar solicitudes POST ilimitadas al endpoint de autenticación, causando un crecimiento ilimitado del archivo de almacenamiento de desafíos y un uso excesivo de CPU y E/S de disco mediante reescrituras repetidas de archivos JSON. -
CVE Modified by [email protected]
Jul. 14, 2026
Action Type Old Value New Value Changed Affected [{'repo': 'https://github.com/nesquena/hermes-webui', 'vendor': 'nesquena', 'product': 'hermes-webui', 'versions': [{'status': 'affected', 'version': '0', 'lessThan': '0.51.270', 'versionType': 'semver'}], 'defaultStatus': 'affected'}] [{'repo': 'https://github.com/nesquena/hermes-webui', 'vendor': 'nesquena', 'product': 'hermes-webui', 'versions': [{'status': 'affected', 'version': '0', 'lessThan': '0.51.270', 'versionType': 'semver'}], 'packageURL': 'pkg:github/nesquena/hermes-webui', 'defaultStatus': 'affected'}] -
CVE Modified 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': '0.51.270', 'versionType': 'semver'}], 'defaultStatus': 'affected'}] -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jun. 17, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-49955', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'yes'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-06-09T18:23:18.415312Z'} -
New CVE Received by [email protected]
Jun. 09, 2026
Action Type Old Value New Value Added Description Hermes WebUI before version 0.51.270 contains a resource exhaustion vulnerability that allows unauthenticated remote attackers to degrade service availability by repeatedly calling the passkey options endpoint without completing assertion. Attackers can send unlimited POST requests to the authentication endpoint, causing unbounded growth of the challenge store file and excessive CPU and disk I/O through repeated JSON file rewrites. 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/58528a4d88b0fa4f7b822e31d6051c669769bd3b Added Reference https://github.com/nesquena/hermes-webui/pull/3624 Added Reference https://github.com/nesquena/hermes-webui/pull/3674 Added Reference https://github.com/nesquena/hermes-webui/releases/tag/v0.51.270 Added Reference https://www.vulncheck.com/advisories/hermes-webui-resource-exhaustion-via-passkey-options