diff --git a/config/security/securityConfig.go b/config/security/securityConfig.go
index 0e9208790..3ecc67fcf 100644
--- a/config/security/securityConfig.go
+++ b/config/security/securityConfig.go
@@ -57,7 +57,8 @@ var DefaultConfig = Config{
 		// foil the obvious SSRF bypass. Public IP literals are collateral
 		// blocks; users who need them can override security.http.urls.
 		URLs: MustNewWhitelist(
-			`(?i)^https?://[a-z]`,
+			`(?i)^https?://[a-z0-9]`,
+			`! ^https?://\d+\.`,
 			`! (?i)localhost`,
 			`! (?i)^https?://[^/?#]*@`,
 		),
diff --git a/config/security/securityConfig_test.go b/config/security/securityConfig_test.go
index 4e120a285..da82b0c49 100644
--- a/config/security/securityConfig_test.go
+++ b/config/security/securityConfig_test.go
@@ -135,7 +135,7 @@ func TestToTOML(t *testing.T) {
 	got := DefaultConfig.ToTOML()
 
 	c.Assert(got, qt.Equals,
-		"[security]\n  enableInlineShortcodes = false\n\n  [security.exec]\n    allow = ['^(dart-)?sass(-embedded)?$', '^go$', '^git$', '^node$', '^postcss$', '^tailwindcss$']\n    osEnv = ['(?i)^((HTTPS?|NO)_PROXY|PATH(EXT)?|APPDATA|TE?MP|TERM|GO\\w+|(XDG_CONFIG_)?HOME|USERPROFILE|SSH_AUTH_SOCK|DISPLAY|LANG|SYSTEMDRIVE|PROGRAMDATA)$']\n\n  [security.funcs]\n    getenv = ['^HUGO_', '^CI$']\n\n  [security.http]\n    methods = ['(?i)GET|POST']\n    urls = ['(?i)^https?://[a-z]', '! (?i)localhost', '! (?i)^https?://[^/?#]*@']\n\n  [security.node]\n    [security.node.permissions]\n      allowAddons = ['tailwindcss']\n      allowChildProcess = ['tailwindcss']\n      allowRead = ['.']\n      allowWorker = ['tailwindcss']\n      allowWrite = []\n      disable = false",
+		"[security]\n  enableInlineShortcodes = false\n\n  [security.exec]\n    allow = ['^(dart-)?sass(-embedded)?$', '^go$', '^git$', '^node$', '^postcss$', '^tailwindcss$']\n    osEnv = ['(?i)^((HTTPS?|NO)_PROXY|PATH(EXT)?|APPDATA|TE?MP|TERM|GO\\w+|(XDG_CONFIG_)?HOME|USERPROFILE|SSH_AUTH_SOCK|DISPLAY|LANG|SYSTEMDRIVE|PROGRAMDATA)$']\n\n  [security.funcs]\n    getenv = ['^HUGO_', '^CI$']\n\n  [security.http]\n    methods = ['(?i)GET|POST']\n    urls = ['(?i)^https?://[a-z0-9]', '! ^https?://\\d+\\.', '! (?i)localhost', '! (?i)^https?://[^/?#]*@']\n\n  [security.node]\n    [security.node.permissions]\n      allowAddons = ['tailwindcss']\n      allowChildProcess = ['tailwindcss']\n      allowRead = ['.']\n      allowWorker = ['tailwindcss']\n      allowWrite = []\n      disable = false",
 	)
 }
 
@@ -273,6 +273,31 @@ func TestCheckAllowedHTTPURLAtInPathIssue14825(t *testing.T) {
 	}
 }
 
+func TestCheckAllowedHTTPURLDigitHostnameIssue14837(t *testing.T) {
+	t.Parallel()
+	c := qt.New(t)
+
+	pc, err := DecodeConfig(config.New())
+	c.Assert(err, qt.IsNil)
+
+	for _, u := range []string{
+		"https://1password.com/",
+		"https://37signals.com/foo",
+	} {
+		c.Assert(pc.CheckAllowedHTTPURL(u), qt.IsNil, qt.Commentf(u))
+	}
+
+	for _, u := range []string{
+		"http://127.0.0.1/",
+		"http://10.0.0.1/",
+		"http://192.168.1.1/",
+		"http://0.0.0.0/",
+	} {
+		err := pc.CheckAllowedHTTPURL(u)
+		c.Assert(err, qt.IsNotNil, qt.Commentf(u))
+	}
+}
+
 func TestDecodeConfigNodePermissions(t *testing.T) {
 	c := qt.New(t)