CVE-2026-55197

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 4.0

7.1CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N

CVSS 3.1

6.5CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

EPSS

0.3% chance of exploitation in the next 30 days; higher than 27% of CVEs (scores of 2026-10-25)

CWE

CWE-639

Published

2026-06-17

Modified

2026-10-26

Record from

the NVD, synced 2026-10-26

References

• https://github.com/nesquena/hermes-webui/commit/2a3baa71b81ca92da8ece8616a09f15894beec71
• https://github.com/nesquena/hermes-webui/pull/3982
• https://github.com/nesquena/hermes-webui/pull/4269
• https://github.com/nesquena/hermes-webui/releases/tag/v0.51.443
• https://www.vulncheck.com/advisories/hermes-webui-broken-access-control-in-api-session-endpoint

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