{"items":[{"id":"NVI-00018341","kind":"vulnerability","title":"Litestar: AllowedHostsMiddleware bypasses host validation via client-controlled X-Forwarded-Host header","revision":1,"unknowns":["Customer inventory, deployment, reachability and exploitation have not been inspected."],"lifecycle":"active","identifiers":["GHSA-3qmc-cj7q-62hv","CVE-2026-48061"],"plain_summary":"GitHub lists this reviewed advisory for litestar. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.","review_status":"source_listed","control_topics":[],"public_actions":[{"summary":"Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.","source_ids":["sr-1387d41141b3bd0f82044a578bbfede0"],"action_type":"investigate","limitations":"Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system.","current_supported_target":null}],"schema_version":"1.1.0","source_metrics":[{"kind":"CVSS","as_of":"2026-06-10T19:12:11.000Z","value":"5.9 medium","meaning":"GitHub source severity; exploitability and local consequence require separate evidence.","source_id":"sr-1387d41141b3bd0f82044a578bbfede0"}],"why_it_matters":"Published affected context helps an owner decide what evidence to gather. This report has not examined your application.","related_sources":[{"id":"sr-1387d41141b3bd0f82044a578bbfede0","url":"https://github.com/advisories/GHSA-3qmc-cj7q-62hv","basis":"vendor_advisory","notes":"GitHub Advisory Database; CC-BY-4.0. Each advisory links its original attribution. Null normalizes fields.","title":"GHSA-3qmc-cj7q-62hv","publisher":"GitHub Advisory Database","observed_at":"2026-11-06T15:13:31.161Z"}],"affected_context":[{"certainty":"source_listed","source_ids":["sr-1387d41141b3bd0f82044a578bbfede0"],"technology":"litestar","known_exclusions":[],"conditions_summary":"### Summary\n\n`AllowedHostsMiddleware` trusts the `X-Forwarded-Host` header as a fallback when the `Host` header is absent. Since `X-Forwarded-Host` is a client-controllable header, an attacker can bypass the allowed hosts validation by omitting the `Host` header and supplying an `X-Forwarded-Host` header set to a whitelisted domain. This enables host header injection attacks such as password reset poisoning, cache poisoning, and server-side request routing manipulation.\n\n### Details\n\nIn `AllowedHostsMiddleware.__call__`, the host value used for validation is resolved as follows:\n\nhttps://github.com/litestar-org/litestar/blob/main/litestar/middleware/allowed_hosts.py#L68\n\n```python\nheaders = MutableScopeHeaders(scope=scope)\nif host := headers.get(\"host\", headers.get(\"x-forwarded-host\", \"\")).split(\":\")[0]:\n    if self.allowed_hosts_regex.fullmatch(host):\n        await self.app(scope, receive, send)\n        return\n```\n\nWhen `Host` is absent (e.g., HTTP/1.0 clients, misconfigured proxies, or raw TCP connections), the middleware falls back to `X-Forwarded-Host` without any verification that the request actually passed through a trusted reverse proxy.\n\nAn attacker can send a request with","public_affected_ranges":["< 2.22.0"]}],"null_published_at":"2026-11-07T07:07:39.819Z","source_updated_at":"2026-06-10T19:12:11.000Z","source_disclosed_at":"2026-06-10T19:12:10.000Z","is_synthetic_fixture":false,"null_last_reviewed_at":null,"public_change_summary":"First indexed by Null; source disclosure date is shown separately.","null_first_observed_at":"2026-11-06T15:13:31.161Z"}],"next_cursor":null,"snapshot_revision":"42594"}