Vulnerability · Published Jun 9, 2026 · Assigned by VulnCheck

CVE-2026-49955Hermes WebUI < 0.51.270 Resource Exhaustion via passkey/options

Medium 5.3

In plain English

A medium-severity resource allocation without limits in hermes-webui from nesquena. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.6% (higher than 48% of all known vulnerabilities).

Severity (CVSS 3.1)5.3Medium

Exploit odds (30 days)0.6%top 51.8% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official 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.

Affected products (as reported)

Vendor	Product	Versions
nesquena	hermes-webui	0 – before 0.51.270

Weakness: CWE-770 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

References

https://github.com/nesquena/hermes-webui/releases/tag/v0.51.270 release-notes
https://github.com/nesquena/hermes-webui/pull/3624 issue-tracking
https://github.com/nesquena/hermes-webui/pull/3674 issue-tracking
https://github.com/nesquena/hermes-webui/commit/58528a4d88b0fa4f7b822e31d6051c669769bd3b patch
https://www.vulncheck.com/advisories/hermes-webui-resource-exhaustion-via-passkey-options third-party-advisory