CVE-2026-49955

Hermes WebUI < 0.51.270 Resource Exhaustion via passkey/options

MEDIUM
5.3
CVSS Score
Published: June 9, 2026 at 04:05 PM UTC
Updated: July 23, 2026 at 07:32 PM UTC
2 products affected across 2 vendorsHermes Web UIHermes WebUI

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Severity
MEDIUM5.3
Exploit prediction
EPSS 0.6%
SSVC
No known exploit

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.

Affected

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

v < 0.51.270
Affected range stops below 0.51.270, so it looks safe — our inference, not a vendor statement
v < 0.51.270
Affected range stops below 0.51.270, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

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

SSVC — Action Prioritization

SSVCNo known exploitAutomatablePartial 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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