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.
CVE-2026-55205
“—” beside the score: it is equal to the CVSS score beside it.
Score 5.3 from GitHub Security Advisory published 2026-06-18. A secondary CVSS source baseline 5.3; sources differ by 0.0.
Also known asEUVD-2026-37904 (ENISA EUVD) · GHSA-hq7f-wv7c-w9mp (GitHub Security Advisories)Source: ENISA EUVD
- CISA's Vulnrichment rates exploitation as PoC; EchelonGraph holds no exploit-code reference for it
A fix is available — apply it.
- CVSS v3
- 5.3
- EG Score
- 5.3MEDIUMmedium confidence
- EG Risk
- 55EG Risk 55/100
EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.
How it’s computed (value × EchelonGraph’s weight)Severity53% × 45%Impact severity (EG Severity): CVSS 5.3 of 10. Never the KEV-floored or EPSS-lifted EG Score.Exploitation40% × 40%EchelonGraph's fixed weight for EG-KEV Tier 3 (Elevated): a constant, not a probability.Automatability100% × 15%CISA's SSVC Automatable value: yes (Vulnrichment).SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Attend at high (mission-essential systems).Exploitation public PoC (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high. - EPSS PROB
- 0.5%
- EPSS %ILE
- 44th
- KEV
- Not listed
What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)
The EG score (5.3): severity, escalated by confirmed exploitation. This CVE's 5.3 is its impact severity (EG Severity), not escalated.
- EG Severity
- 5.3 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
- EG Likelihood
- 0.5% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-29). FIRST's exploitation probability, not an EchelonGraph model.
- Confirmed exploitation
- None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
- EG Priority
- SSVC Track at medium mission impactTrack at low or medium mission impact; Attend at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; 60 days if it is not.Each input and its source: the SSVC and BOD 26-04 blocks below.
SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Attend at high (mission-essential systems).
A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
Exploitation public PoC (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table
BOD 26-04 (CISA's remediation timeline, Table 1)14 days if the affected system is publicly exposed; 60 days if it is not.
In CISA KEV no (CISA's KEV catalog) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it
Published
June 18, 2026
Last Modified
October 26, 2026
Advisory Details (5)
Auto-updated Jun 18, 2026[security] fix(oauth): reuse pending onboarding flows
Upstream fix in progress (PR #3970 · nesquena/hermes-webui, state=closed)
https://github.com/nesquena/hermes-webui/pull/3970Hermes WebUI < 0.51.468 - Resource Exhaustion via Unauthenticated OAuth Flow Endpoint | Advisories | VulnCheck
https://www.vulncheck.com/advisories/hermes-webui-resource-exhaustion-via-unauthenticated-oauth-flow-endpointv0.51.468
Patch available: nesquena/hermes-webui v0.51.468
https://github.com/nesquena/hermes-webui/releases/tag/v0.51.468Release v0.51.468 — onboarding OAuth single-flight (#3970)
Patch available: nesquena/hermes-webui v0.51.470 (PR #4338 merged 2026-06-17)
https://github.com/nesquena/hermes-webui/pull/4338commit ce272d9cd5f8 (nesquena/hermes-webui)
Patch available: nesquena/hermes-webui v0.51.470 (contains commit ce272d9cd5f8)
https://github.com/nesquena/hermes-webui/commit/ce272d9cd5f8e5a4521278f56eb5388010901646Vendor Advisories for CVE-2026-55205(1)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 12× in last 7d / 43× in last 30d)
Each row is a time one of our pipelines fetched, updated or re-scored this CVE. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.
Showing the most recent 100 of 238 refreshes on record for this CVE.
A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. None are among the latest 100 rows. The 138 oldest rows on record are not shown and were not checked, so the counts can still include repeats.
- 2026-10-30 16:34 UTCEPSS rescoreEPSS 0.5% · 44th percentile
- 2026-10-29 16:34 UTCEG score recompute
- 2026-10-29 16:34 UTCGHSA enrichmentGHSA-hq7f-wv7c-w9mp · GitHub CVSS 5.3
- 2026-10-29 16:33 UTCEPSS rescoreEPSS 0.5% · 44th percentile
- 2026-10-28 16:32 UTCEPSS rescoreEPSS 0.5% · 44th percentile
- 2026-10-27 16:32 UTCEPSS rescoreEPSS 0.5% · 44th percentile
- 2026-10-26 16:31 UTCEPSS rescoreEPSS 0.5% · 44th percentile
- 2026-10-26 00:29 UTCEG score recompute
- 2026-10-26 00:29 UTCGHSA enrichmentGHSA-hq7f-wv7c-w9mp · GitHub CVSS 5.3
- 2026-10-25 16:33 UTCEPSS rescoreEPSS 0.5% · 44th percentile
- 2026-10-25 14:19 UTCEG score recompute
- 2026-10-24 16:33 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
- 2026-10-23 16:32 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
- 2026-10-22 21:16 UTCEG score recompute
- 2026-10-22 21:16 UTCGHSA enrichmentGHSA-hq7f-wv7c-w9mp · GitHub CVSS 5.3
- 2026-10-22 16:34 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
- 2026-10-21 16:33 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
- 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
- 2026-10-19 16:32 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
- 2026-10-18 16:32 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
- 2026-10-18 03:30 UTCEG score recompute
- 2026-10-17 16:34 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
- 2026-10-16 16:42 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
- 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
- 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
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- 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
- 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
- 2026-10-12 15:56 UTCEG score recompute
- 2026-10-11 19:39 UTCEG score recompute
- 2026-10-11 16:54 UTCEG score recompute
- 2026-10-11 14:17 UTCEG score recompute
- 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
- 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
- 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
- 2026-10-08 17:12 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
- 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
- 2026-10-07 13:05 UTCOSV refresh
- 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
- 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
- 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
- 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
- 2026-10-02 17:56 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
- 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
- 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
- 2026-09-29 15:22 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
- 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
- 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
- 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
- 2026-09-24 14:04 UTCEPSS rescoreEPSS 0.5% · 41st percentile
- 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.4% · 30th percentile
- 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.4% · 30th percentile
- 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.4% · 30th percentile
- 2026-09-17 19:31 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
- 2026-09-17 19:11 UTCGHSA enrichmentGHSA-hq7f-wv7c-w9mp · GitHub CVSS 5.3
- 2026-09-17 18:16 UTCEG score recompute
- 2026-09-17 18:16 UTCGHSA enrichmentGHSA-hq7f-wv7c-w9mp · GitHub CVSS 5.3
- 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
- 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
- 2026-09-15 03:11 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
- 2026-09-13 16:47 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
- 2026-09-13 13:53 UTCEG score recompute
- 2026-09-13 13:53 UTCGHSA enrichmentGHSA-hq7f-wv7c-w9mp · GitHub CVSS 5.3
- 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
- 2026-09-10 09:35 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
- 2026-09-08 22:01 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
- 2026-09-07 16:01 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
- 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
- 2026-09-04 05:06 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
- 2026-09-02 14:12 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
- 2026-09-01 13:54 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
- 2026-09-01 04:40 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
- 2026-08-30 20:55 UTCEG score recompute
- 2026-08-30 20:55 UTCGHSA enrichmentGHSA-hq7f-wv7c-w9mp · GitHub CVSS 5.3
- 2026-08-30 19:17 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
- 2026-08-30 01:22 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
- 2026-08-28 21:41 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
- 2026-08-27 14:25 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
- 2026-08-26 14:46 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
- 2026-08-25 13:49 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
- 2026-08-24 22:19 UTCEG score recompute
- 2026-08-24 22:19 UTCGHSA enrichmentGHSA-hq7f-wv7c-w9mp · GitHub CVSS 5.3
- 2026-08-23 23:17 UTCGHSA enrichmentGHSA-hq7f-wv7c-w9mp · GitHub CVSS 5.3
- 2026-08-23 01:07 UTCEG score recompute
- 2026-08-23 01:07 UTCGHSA enrichmentGHSA-hq7f-wv7c-w9mp · GitHub CVSS 5.3
- 2026-08-23 00:19 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
- 2026-08-21 23:49 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
- 2026-08-21 06:21 UTCEG score recompute
- 2026-08-21 06:21 UTCGHSA enrichmentGHSA-hq7f-wv7c-w9mp · GitHub CVSS 5.3
- 2026-08-20 22:55 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
- 2026-08-20 08:08 UTCEG score recompute
- 2026-08-20 08:08 UTCGHSA enrichmentGHSA-hq7f-wv7c-w9mp · GitHub CVSS 5.3
- 2026-08-19 17:04 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
- 2026-08-19 07:43 UTCEG score recompute
- 2026-08-19 07:43 UTCGHSA enrichmentGHSA-hq7f-wv7c-w9mp · GitHub CVSS 5.3
- 2026-08-18 13:48 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
- 2026-08-17 13:47 UTCEPSS rescoreEPSS 0.5% · 41st percentile
- 2026-08-16 20:41 UTCEG score recompute
- 2026-08-16 20:41 UTCGHSA enrichmentGHSA-hq7f-wv7c-w9mp · GitHub CVSS 5.3
- 2026-08-16 14:56 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
- 2026-08-16 02:14 UTCEPSS rescoreEPSS 0.5% · 41st percentile
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Frequently asked(5)
What is CVE-2026-55205?
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What is the CVSS score of CVE-2026-55205?
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Dependency Blast Radius
Explore the affected products and dependency analysis for CVE-2026-55205
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