CVE-2026-55205

Hermes WebUI < 0.51.468 - Resource Exhaustion via Unauthenticated OAuth Flow Endpoint

MEDIUM
5.3
CVSS Score
Published: June 18, 2026 at 03:49 PM UTC
Updated: October 26, 2026 at 12:10 AM UTC
2 products affected across 2 vendorsHermes Web UIHermes WebUI

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Severity
MEDIUM5.3
Exploit prediction
EPSS 0.5%
SSVC
PoC

Description

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 0.51.468
Affected range stops below 0.51.468, so it looks safe — our inference, not a vendor statement
v < 0.51.468
Vendor states this is fixed in 0.51.468 (unaffected)

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

SSVC — Action Prioritization

SSVCPoCAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

5.3MEDIUMVulnCheck
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
LOW
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-770

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