Which versions of Hermes WebUI are affected by CVE-2026-49956?

Hermes WebUI before version 0.51.269 allows any authenticated user to access other users' private session data, including conversation titles and message transcripts, due to improper access control…. A patch is available.

How to fix or mitigate CVE-2026-49956?

Within 24 hours: Confirm whether Hermes WebUI is deployed in production and document all instances and versions. Within 7 days: Upgrade all instances to Hermes WebUI 0.51.269 or later, and review server-side access logs for evidence of cross-profile queries. Within 30 days: Conduct full audit of access control implementations in Hermes WebUI and dependent systems to identify similar scoping failures.

Hermes WebUI CVE-2026-49956

Q: What is the CVSS score of CVE-2026-49956?

CVE-2026-49956 has a CVSS 4.0 base score of 7.1 (High). CVSS vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X. EPSS exploitation probability: 0.0%.

EUVD-2026-35497 HIGH

Missing Authorization (CWE-862)

2026-06-09 VulnCheck

GHSA-mgxw-v6rh-wcv6

Authentication Bypass Hermes Webui

7.1

CVSS 4.0 · Vendor: VulnCheck

Severity by source

Vendor (VulnCheck) PRIMARY

7.1 HIGH

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Primary rating from Vendor (VulnCheck) · only source for this CVE.

CVSS VectorVendor: VulnCheck

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Lifecycle Timeline

Analysis Updated

Jun 09, 2026 - 17:29 vuln.today

v3 (cvss_changed)

Analysis Updated

Jun 09, 2026 - 17:29 vuln.today

v2 (cvss_changed)

Re-analysis Queued

Jun 09, 2026 - 17:22 vuln.today

cvss_changed

Severity Changed

Jun 09, 2026 - 17:22 NVD

MEDIUM HIGH

CVSS changed

Jun 09, 2026 - 17:22 NVD

6.5 (MEDIUM) 7.1 (HIGH)

Source Code Evidence Fetched

Jun 09, 2026 - 16:52 vuln.today

Analysis Generated

Jun 09, 2026 - 16:52 vuln.today

DescriptionCVE.org

Hermes WebUI before version 0.51.269 contains a profile isolation bypass vulnerability that allows authenticated users to access data belonging to other profiles by querying the session search endpoint without active-profile filtering. Attackers can send requests to the sessions search handler to retrieve session titles and transcript message content from profiles other than their own active profile.

AnalysisAI

Cross-profile data disclosure in Hermes WebUI before 0.51.269 allows authenticated users to read session titles and transcript message content from other users' profiles by querying the sessions search endpoint, which fails to scope results to the caller's active profile. The flaw was reported by VulnCheck and a vendor patch is available; no public exploit identified at time of analysis, but the issue is trivial to trigger for any logged-in account.

Technical ContextAI

Hermes WebUI is a Node/web front-end (CPE cpe:2.3:a:nesquena:hermes-webui) that organizes conversation sessions under per-user 'profiles' for isolation. The root cause is CWE-862 (Missing Authorization): the sessions search handler executes the query without applying the active-profile filter that the rest of the application relies on for tenant separation, so authorization is enforced inconsistently across endpoints. The disclosed data includes user-generated session titles and transcript message bodies, meaning any sensitive content typed into chats is reachable through the same handler.

RemediationAI

Vendor-released patch: upgrade to Hermes WebUI 0.51.269 or later, which lands the fix tracked in pull requests https://github.com/nesquena/hermes-webui/pull/3646 and https://github.com/nesquena/hermes-webui/pull/3672 and commit https://github.com/nesquena/hermes-webui/commit/2c7b530071bb29ae4184e83e33be5799d529568e. Until the upgrade can be deployed on multi-user instances, restrict access to the sessions search endpoint at the reverse proxy (for example, block or require an additional auth header on the sessions search route) and consider running each user in an isolated single-profile deployment; both controls degrade search functionality or increase operational overhead but eliminate cross-profile reads. Monitor application logs for unusual volumes of sessions search queries from low-privilege accounts and rotate any chat content that may have been exposed.