CVE-2026-49955

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.

References

• https://github.com/nesquena/hermes-webui/commit/58528a4d88b0fa4f7b822e31d6051c669769bd3b
• https://github.com/nesquena/hermes-webui/pull/3624
• https://github.com/nesquena/hermes-webui/pull/3674
• https://github.com/nesquena/hermes-webui/releases/tag/v0.51.270
• https://www.vulncheck.com/advisories/hermes-webui-resource-exhaustion-via-passkey-options