{"items":[{"id":"NVI-00013202","kind":"vulnerability","title":"http4k: `reverseProxy()` defaulted to substring (`Contains`) matching on `Host`; tightened to `Exact`","revision":1,"unknowns":["Customer inventory, deployment, reachability and exploitation have not been inspected."],"lifecycle":"active","identifiers":["GHSA-jrpc-7vxp-69p6"],"plain_summary":"GitHub lists this reviewed advisory for org.http4k:http4k-core, org.http4k:http4k-core, org.http4k:http4k-core. 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-8d5f3936d0ecdc87a135ed9307d6aa95"],"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":[],"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-8d5f3936d0ecdc87a135ed9307d6aa95","url":"https://github.com/advisories/GHSA-jrpc-7vxp-69p6","basis":"vendor_advisory","notes":"GitHub Advisory Database; CC-BY-4.0. Each advisory links its original attribution. Null normalizes fields.","title":"GHSA-jrpc-7vxp-69p6","publisher":"GitHub Advisory Database","observed_at":"2026-11-01T07:25:10.521Z"}],"affected_context":[{"certainty":"source_listed","source_ids":["sr-8d5f3936d0ecdc87a135ed9307d6aa95"],"technology":"org.http4k:http4k-core","known_exclusions":[],"conditions_summary":"### Impact\n\n`reverseProxy()` and `reverseProxyRouting()` matched configured vhosts by substring on the `Host` header (`Contains` matcher) by default. The intended use of these functions in http4k is **outbound dispatch** (e.g. matching AWS service subdomains, per the `Contains` docstring) and **test-time composition** of fake backend networks. In either of those contexts the matched `Host` is set by the calling application, not by an external attacker, so the loose match has no exploit surface.\n\nIf, however, `reverseProxy()` was deployed as a public-facing inbound HTTP handler — which the function technically supports but is not the documented intent — an external attacker could send `Host: admin.evil.com` and reach a vhost configured as `admin`, bypassing routing-based authorization.\n\nThe `Contains` matcher's docstring explicitly documented this loose behaviour, but because `Contains` was the default, callers who never read the matcher docs would still get the loose behaviour.\n\n**Who is affected:** only deployments using `reverseProxy()` / `reverseProxyRouting()` as a public-facing inbound HTTP handler with two or more configured virtual hosts. The intended outbound / test-time us","public_affected_ranges":[">= 5.0.0.0, < 5.42.0.0"]},{"certainty":"source_listed","source_ids":["sr-8d5f3936d0ecdc87a135ed9307d6aa95"],"technology":"org.http4k:http4k-core","known_exclusions":[],"conditions_summary":"### Impact\n\n`reverseProxy()` and `reverseProxyRouting()` matched configured vhosts by substring on the `Host` header (`Contains` matcher) by default. The intended use of these functions in http4k is **outbound dispatch** (e.g. matching AWS service subdomains, per the `Contains` docstring) and **test-time composition** of fake backend networks. In either of those contexts the matched `Host` is set by the calling application, not by an external attacker, so the loose match has no exploit surface.\n\nIf, however, `reverseProxy()` was deployed as a public-facing inbound HTTP handler — which the function technically supports but is not the documented intent — an external attacker could send `Host: admin.evil.com` and reach a vhost configured as `admin`, bypassing routing-based authorization.\n\nThe `Contains` matcher's docstring explicitly documented this loose behaviour, but because `Contains` was the default, callers who never read the matcher docs would still get the loose behaviour.\n\n**Who is affected:** only deployments using `reverseProxy()` / `reverseProxyRouting()` as a public-facing inbound HTTP handler with two or more configured virtual hosts. The intended outbound / test-time us","public_affected_ranges":["< 4.51.0.0"]},{"certainty":"source_listed","source_ids":["sr-8d5f3936d0ecdc87a135ed9307d6aa95"],"technology":"org.http4k:http4k-core","known_exclusions":[],"conditions_summary":"### Impact\n\n`reverseProxy()` and `reverseProxyRouting()` matched configured vhosts by substring on the `Host` header (`Contains` matcher) by default. The intended use of these functions in http4k is **outbound dispatch** (e.g. matching AWS service subdomains, per the `Contains` docstring) and **test-time composition** of fake backend networks. In either of those contexts the matched `Host` is set by the calling application, not by an external attacker, so the loose match has no exploit surface.\n\nIf, however, `reverseProxy()` was deployed as a public-facing inbound HTTP handler — which the function technically supports but is not the documented intent — an external attacker could send `Host: admin.evil.com` and reach a vhost configured as `admin`, bypassing routing-based authorization.\n\nThe `Contains` matcher's docstring explicitly documented this loose behaviour, but because `Contains` was the default, callers who never read the matcher docs would still get the loose behaviour.\n\n**Who is affected:** only deployments using `reverseProxy()` / `reverseProxyRouting()` as a public-facing inbound HTTP handler with two or more configured virtual hosts. The intended outbound / test-time us","public_affected_ranges":[">= 6.0.0.0, < 6.49.0.0"]}],"null_published_at":"2026-11-01T07:29:12.929Z","source_updated_at":"2026-09-24T14:57:45.000Z","source_disclosed_at":"2026-06-19T21:15:59.000Z","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":"2026-11-01T07:25:10.521Z"}],"next_cursor":null,"snapshot_revision":"42594"}