diff --git a/cmd/prometheus/main.go b/cmd/prometheus/main.go
index 1d844ddba..787a28992 100644
--- a/cmd/prometheus/main.go
+++ b/cmd/prometheus/main.go
@@ -343,7 +343,7 @@ func main() {
 	a.Flag("web.page-title", "Document title of Prometheus instance.").
 		Default("Prometheus Time Series Collection and Processing Server").StringVar(&cfg.web.PageTitle)
 
-	a.Flag("web.cors.origin", `Regex for CORS origin. It is fully anchored. Example: 'https?://(domain1|domain2)\.com'`).
+	a.Flag("web.cors.origin", `Regex for CORS origin. It is fully anchored. Example: 'https?://(domain1\|domain2)\.com'`).
 		Default(".*").StringVar(&cfg.corsRegexString)
 
 	serverOnlyFlag(a, "storage.tsdb.path", "Base path for metrics storage.").
diff --git a/docs/command-line/prometheus.md b/docs/command-line/prometheus.md
index 223260243..2faf65105 100644
--- a/docs/command-line/prometheus.md
+++ b/docs/command-line/prometheus.md
@@ -30,7 +30,7 @@ The Prometheus monitoring server
 | <code class="text-nowrap">--web.console.templates</code> | Path to the console template directory, available at /consoles. | `consoles` |
 | <code class="text-nowrap">--web.console.libraries</code> | Path to the console library directory. | `console_libraries` |
 | <code class="text-nowrap">--web.page-title</code> | Document title of Prometheus instance. | `Prometheus Time Series Collection and Processing Server` |
-| <code class="text-nowrap">--web.cors.origin</code> | Regex for CORS origin. It is fully anchored. Example: 'https?://(domain1|domain2)\.com' | `.*` |
+| <code class="text-nowrap">--web.cors.origin</code> | Regex for CORS origin. It is fully anchored. Example: 'https?://(domain1\|domain2)\.com' | `.*` |
 | <code class="text-nowrap">--storage.tsdb.path</code> | Base path for metrics storage. Use with server mode only. | `data/` |
 | <code class="text-nowrap">--storage.tsdb.retention</code> | [DEPRECATED] How long to retain samples in storage. This flag has been deprecated, use "storage.tsdb.retention.time" instead. Use with server mode only. |  |
 | <code class="text-nowrap">--storage.tsdb.retention.time</code> | How long to retain samples in storage. When this flag is set it overrides "storage.tsdb.retention". If neither this flag nor "storage.tsdb.retention" nor "storage.tsdb.retention.size" is set, the retention time defaults to 15d. Units Supported: y, w, d, h, m, s, ms. Use with server mode only. |  |