Hermes Agent 0.18.2 prior to 0.19.0 contains a supply chain vulnerability in its bundled MCP catalog that allows a remote attacker to execute arbitrary code by compromising a third-party upstream repository referenced via a mutable branch rather than a pinned commit SHA. An attacker who compromises the upstream repository can propagate malicious code to every host that installs the affected catalog entry, with no further action required by the operator.

Hermes WebUI before 0.51.468 contains a resource exhaustion vulnerability in the unauthenticated POST /api/onboarding/oauth/start endpoint that allows unbounded accumulation of in-memory flow state and daemon threads. Attackers can send repeated or concurrent requests to exhaust server memory and thread resources, potentially triggering repeated outbound device-code requests to upstream OAuth providers.

Hermes WebUI before 0.51.443 contains an authorization bypass vulnerability in the session export endpoint that allows authenticated users to access sessions from other profiles. The handlesessionexport handler in api/routes.py fails to verify active-profile ownership before serializing session data, enabling attackers to exfiltrate foreign session transcripts by guessing or knowing session identifiers.

Hermes WebUI before 0.51.409 contains an authentication bypass vulnerability in passkey registration endpoints that allows unauthenticated remote attackers to register arbitrary passkeys. When HERMESWEBUIPASSKEY=1 is enabled with no existing credentials, POST /api/auth/passkey/register/options and POST /api/auth/passkey/register endpoints are accessible without authentication, allowing attackers to claim the first passkey and gain permanent administrative control.

Hermes WebUI before 0.51.368 contains an authorization bypass vulnerability in the getprofilecookie() function that accepts unauthenticated profile names from the hermesprofile cookie. An authenticated attacker can forge the hermesprofile cookie value to bypass profile-scoped authorization checks and access sessions, files, and resources across different profiles.

Hermes WebUI before version 0.51.358 contains an improper access control vulnerability that allows unauthenticated remote attackers to hijack initial setup by submitting the setpassword parameter to the settings API endpoint without any network origin restriction. Attackers on any reachable network can send a POST request to the settings endpoint during the first-run setup window to persist an arbitrary password hash, obtain a valid session cookie, and lock out the legitimate operator from their own instance.

Hermes WebUI before version 0.51.311 contains a remote code execution vulnerability that allows authenticated attackers to execute arbitrary commands by placing malicious executable Git configuration in a workspace repository's .git/config file. Attackers can exploit Git subprocess invocations in api/workspacegit.py through vectors such as core.fsmonitor during git status, protocol.ext.allow with ext:: remotes during git fetch, credential.helper, core.askPass, core.gitProxy, or inherited environment variables including GITSSHCOMMAND to achieve arbitrary command execution on the host running the application.

Hermes WebUI before version 0.51.303 contains a time-of-check time-of-use (TOCTOU) race condition vulnerability in the gitdiscard function within api/workspacegit.py that allows attackers to delete files outside the configured workspace boundary by replacing a validated path component with a symlink after validation but before deletion. Attackers can substitute a workspace-controlled path component with a symlink pointing to an external directory between the saferesolvews() validation step and the subsequent Path.unlink() or shutil.rmtree() deletion call, causing the delete operation to follow the symlink and remove arbitrary files outside the workspace.

Hermes WebUI before version 0.51.296 contains a workspace boundary bypass vulnerability that allows authenticated attackers to circumvent blocked-root path checks by exploiting an early return in the SSH/remote terminal profile workspace resolution logic within remoteterminalworkspacecandidate(). Attackers can configure a remote terminal working directory to a system directory such as /etc, causing the workspace resolution path to accept it as a trusted local workspace root before the isblockedworkspacepath() guard executes, enabling read access to local system files through workspace file-read helpers.

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.

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.

Hermes WebUI prior to v0.51.221 contains a path traversal vulnerability that allows attackers to escape the workspace boundary by supplying symlinks that resolve to files or directories outside the designated workspace root. Attackers can exploit the workspace file and listing APIs, which resolve symlink targets without enforcing that the final path remains within the workspace, to read external host files accessible to the server process and disclose sensitive data such as SSH keys, cloud credentials, or application tokens.

Hermes WebUI prior to 0.51.44 contains a path traversal vulnerability in the session import endpoint that allows authenticated attackers to read arbitrary files by importing a crafted session with an unrestricted workspace value. Attackers can supply a blocked filesystem root in the workspace field and subsequently use relative paths in the session file API to access any file readable by the WebUI process.