CVE-2026-55205

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.

CVSS 4.0

6.9CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N

CVSS 3.1

5.3CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

EPSS

0.5% chance of exploitation in the next 30 days; higher than 44% of CVEs (scores of 2026-10-25)

CWE

CWE-770

Published

2026-06-18

Modified

2026-10-26

Record from

the NVD, synced 2026-10-26

References

• https://github.com/nesquena/hermes-webui/commit/ce272d9cd5f8e5a4521278f56eb5388010901646
• https://github.com/nesquena/hermes-webui/pull/3970
• https://github.com/nesquena/hermes-webui/pull/4338
• https://github.com/nesquena/hermes-webui/releases/tag/v0.51.468
• https://www.vulncheck.com/advisories/hermes-webui-resource-exhaustion-via-unauthenticated-oauth-flow-endpoint

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