6.9

CVE-2026-49955: Hermes WebUI < 0.51.270 Resource Exhaustion via passkey/options

Deferred
Published 09-06-2026Last modified 14-07-2026

Vulnerability summary

CVE-2026-49955 is a medium (CVSS 6.9) vulnerability in nesquena hermes-webui. EPSS estimates a 0.78% chance of exploitation in the next 30 days, higher than 55.5% of scored vulnerabilities.

Overall risk
28/100
0100
Medium · default modelHow is this calculated?
CVSS score
6.9/10
010
Medium · v4.0 (CVE.org)
EPSS score
0.78%
0%100%
Low · +0.20 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Timeline

  1. 09-06-2026
    PublishedVulnerability first disclosed.
  2. 14-07-2026
    Last modifiedVulnerability information updated.

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.

CVSS metrics

4 scores · 2 sources · 2 versions

EPSS trend

Probability

0.78%

Chance of exploitation in the next 30 days

Percentile

56%

Versus all other CVEs

30-day change

Increase +0.20 pp

From 0.59% on 22-09-2026

22-09-202622-10-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Nesquena1 product

1 vendor · 1 product

References

5 links