7.1

CVE-2026-55197: Hermes WebUI < 0.51.443 - Broken Access Control in /api/session Endpoint

Deferred
Published 17-06-2026Last modified 17-09-2026

Vulnerability summary

CVE-2026-55197 is a high (CVSS 7.1) vulnerability in nesquena hermes-webui. EPSS estimates a 0.47% chance of exploitation in the next 30 days, higher than 40% of scored vulnerabilities.

Overall risk
28/100
0100
Medium · default modelHow is this calculated?
CVSS score
7.1/10
010
High · v4.0 (CVE.org)
EPSS score
0.47%
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. 17-06-2026
    PublishedVulnerability first disclosed.
  2. 17-09-2026
    Last modifiedVulnerability information updated.

Description

Hermes WebUI before 0.51.443 contains a broken access control vulnerability in the /api/session endpoint that allows authenticated users to disclose cross-profile session transcripts. Attackers can bypass profile boundary checks by directly querying session IDs belonging to other profiles via GET /api/session?session_id=<foreign_id>&messages=1 to retrieve unauthorized conversation transcripts and metadata.

CVSS metrics

4 scores · 2 sources · 2 versions

EPSS trend

Probability

0.47%

Chance of exploitation in the next 30 days

Percentile

40%

Versus all other CVEs

30-day change

Increase +0.20 pp

From 0.27% 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