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TI-2026-39877 Aliases CVE-2026-55197GHSA-5wqv-fhmr-pjgh

Hermes WebUI < 0.51.443 - Broken Access Control in /api/session Endpoint

Priority MEDIUM 64CWE-639Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
Security bypass
Confidentiality · integrity · availability
High · None · None
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-639.

Summary

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.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00346 28th percentileScored 2026-11-07
Fix Fixed hermes-webui (nesquena): 0.51.443

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
nesquenahermes-webuibefore 0.51.4430.51.443Patch availableCNA
  • hermes-webui Vendornesquena Affected before 0.51.443 Fixed in 0.51.443 Patch available CNA

Remediation

  • Fix · CNA hermes-webui (nesquena) Fixed in 0.51.443

Fixed in the same release

Records fixed by the same vendor advisory or release, as the CNA lists them.

  • Release ·

    nesquena hermes-webui 0.51.443

    2 records Highest priority Priority MEDIUM 2 MEDIUM

    Other records, highest priority first

    • TI-2026-39878 Hermes WebUI < 0.51.443 - Cross-Profile Session Data Exfiltration via Session Export EndpointPriority MEDIUM 64
    Show all 2 records →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-55197
  2. 2026-10-03 Alias added: GHSA-5wqv-fhmr-pjgh

References

Patch 3

Other 1

  • TI-2026-36807 Hermes WebUI < 0.51.358 Unauthenticated Password Takeover via /api/settings CVSS 4.0CRITICAL 9.2
  • TI-2026-39885 Hermes WebUI < 0.51.468 - Resource Exhaustion via Unauthenticated OAuth Flow Endpoint CVSS 4.0MEDIUM 6.9
  • TI-2026-39878 Hermes WebUI < 0.51.443 - Cross-Profile Session Data Exfiltration via Session Export Endpoint CVSS 4.0HIGH 7.1
  • TI-2026-36799 Hermes WebUI < 0.51.269 Profile Isolation Bypass via sessions search CVSS 4.0HIGH 7.1
  • TI-2026-09773 Hermes WebUI before 0.51.221 Path Traversal via Symlink Workspace Bypass CVSS 4.0HIGH 7.1
  • TI-2026-41892 Hermes WebUI < 0.51.521 - Cross-Profile Authorization Bypass via Unset Session Profile on Import CVSS 4.0MEDIUM 6.0
See all 16 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences