CVE-2026-55428

In Coder prior to versions 2.24.5, 2.29.13, 2.30.8, 2.31.12, 2.32.2, and 2.33.3, the `azureidentity.Validate()` function does not verify the PKCS#7 signature, only checking that the signer certificate chains to a trusted Azure CA. An attacker can embed a legitimate Azure certificate alongside arbitrary content, e.g., `{"vmId":"<target>"}`, and the forged `vmId` will be accepted, returning the victim workspace agent's session token.

Coder before 2.29.21, 2.30.0 before 2.34.12, 2.35.0 before 2.35.9, 2.36.0 before 2.36.7, and 2.37.0 before 2.37.4 does not validate the audience claim of GCE instance-identity JWTs at the POST /api/v2/workspaceagents/google-instance-identity endpoint. Attackers who obtain an unexpired format=full identity token minted for another relying party can replay it to obtain that workspace agent's session token, which remains valid until the workspace's next build.

Coder before 2.34.7 contains an IP spoofing vulnerability in the ExtractRealIPAddress middleware that trusts the leftmost, client-supplied X-Forwarded-For value instead of the client IP appended by a reverse proxy. Attackers can send forged X-Forwarded-For values through appending proxies to bypass per-IP rate limits on login, one-time passcode, and password validation endpoints, enabling brute-force attacks, and to falsify IP addresses recorded in audit logs.

Coder before 2.29.17, 2.30.0 before 2.32.7, 2.33.0 before 2.33.8, and 2.34.0 before 2.34.2 contains a user enumeration vulnerability because userpassword.Compare() substitutes a placeholder hash derived from the string "hunter2" when a stored password hash is empty. Unauthenticated attackers can submit logins with the password "hunter2" and distinguish HTTP 403 from 401 responses to enumerate valid accounts and reveal the authentication provider of SSO-only users.

Coder before 2.29.17, 2.30.0 before 2.32.7, 2.33.0 before 2.33.8, and 2.34.0 before 2.34.2 contains a stored HTML injection vulnerability because the ApplicationName and LogoURL appearance settings are rendered into HTML output without sufficient escaping. Attackers with the Owner role can store HTML markup in these settings that renders in the Coder dashboard and in SMTP notification emails sent to other deployment users.

Coder from 2.0.0 before 2.34.8 contains an open redirect vulnerability in handleAPIKeySmuggling that allows attackers to redirect users externally via unsanitized r.URL.Path values. Attackers can craft links on trusted workspace app subdomains with paths beginning with double slashes, which become scheme-relative redirects to attacker sites for phishing.

Coder from 2.26.0 before 2.34.8 contains an incorrect authorization flaw in the GET /api/v2/workspaces/{id}/acl endpoint, which checks only workspace read access and then fetches group members using an elevated system context. Authenticated users granted workspace use access can query the endpoint to harvest group members' emails, login types, status, and last-seen and creation timestamps.

Coder from 2.30.0 before 2.34.8 contains an authorization bypass vulnerability in the provisioner daemon DownloadFile gRPC handler that allows authenticated provisioner daemons to download other organizations' cached Terraform module archives. Attackers with an org-scoped provisioner key and a known file UUID can retrieve module source code exposing infrastructure topology or embedded secrets.

Coder from 2.0.0 before 2.34.8 contains an incorrect authorization vulnerability in the acl_allow rule of coderd/rbac/policy.rego, which does not verify organization membership for per-user ACL entries, and organization member removal does not scrub those entries. Authenticated users removed from an organization can keep accessing previously granted org-scoped resources such as templates and workspaces via the API.

Coder before 2.29.20, 2.33.0 before 2.33.12, 2.34.0 before 2.34.8, and 2.35.0 before 2.35.4 contains an improper hostname validation flaw in GetWorkspaceProxyByHostname whose SIMILAR TO pattern performs a prefix match, so any domain that is a string prefix of a workspace-proxy access URL is trusted as a proxy. Attackers owning such a domain can lure an authenticated victim to a crafted /api/v2/applications/auth-redirect link, capture the redirected application_connect API key, and replay it to access the victim's workspace apps.