Resource exhaustion in Nesquena Hermes-Webui
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L.
EPSS exploit prediction
EPSS: 0.005 (42.1th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 42nd percentile — 42.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.005 · newest: 0.005 · change: 0.000
Affected products
- Nesquena Hermes-Webui — versions 0, 0.51.468
Weakness classification (CWE)
References
- github.com/nesquena/hermes-webui/releases/tag/v0.51.468 (release-notes)
- github.com/nesquena/hermes-webui/pull/3970 (issue-tracking, technical-description, patch)
- github.com/nesquena/hermes-webui/pull/4338 (issue-tracking, patch)
- github.com/nesquena/hermes-webui/commit/ce272d9cd5f8e5a4521278f56eb5388010901646 (patch)
- www.vulncheck.com/advisories/hermes-webui-resource-exhaustion-via-unauthenticat… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-55205?
- CVE-2026-55205 is a medium-severity vulnerability in Nesquena Hermes-Webui, classified under Allocation of Resources Without Limits or Throttling. CVSS score: 5.3/10. Published 2026-06-18.
- How severe is CVE-2026-55205?
- Medium severity. CVSS v3 base score is 5.3 out of 10.