a1d7c07c50f1d895337de121680ea672b261c058
max
  Mon Aug 17 02:26:36 2026 -0700
escape reflected/echoed user input across several CGIs (XSS), refs #38057

Route user-, DB- and hub-derived values through htmlEncode (HTML/attribute text),
cgiEncode (values composed into URLs), jsonStringEscape (values placed in a JS string
literal inside an inline script) or, for hgMirror, the existing mustBeClean sanitizer.
Covers hgHubConnect, hgUserSuggestion, hgLiftOver, hgBlat, hgc pubs, hgVisiGene,
hgSession, hgTrackUi, hgGenome, phyloPng, hgFileSearch, hgLinkIn, hgPal, hui,
hgPhyloPlace, hgMirror, hgCustom and hgSearch.

diff --git src/hg/lib/hui.c src/hg/lib/hui.c
index 19e5c9a0ddb..e7e26e49800 100644
--- src/hg/lib/hui.c
+++ src/hg/lib/hui.c
@@ -6090,31 +6090,31 @@
 
 char defaultColor[16];
 safef(defaultColor, sizeof(defaultColor), "#%02x%02x%02x", tdb->colorR, tdb->colorG, tdb->colorB);
 
 char *rawCartValue = cartOptionalString(cart, varName);
 boolean hasOverride = (rawCartValue != NULL && rawCartValue[0] != '\0');
 char *colorValue = hasOverride ? rawCartValue : defaultColor;
 
 char checkVar[1024];
 safef(checkVar, sizeof(checkVar), "%s.colorOverrideOn", name);
 boolean isOn = cartUsualBoolean(cart, checkVar, hasOverride);
 
 printf("<br><b>Override track color:</b> ");
 cgiMakeCheckBox(checkVar, isOn);
 printf(" <input type='text' name='%s' id='%s_text' value='%s' size='8' />",
-    varName, varName, colorValue);
+    varName, varName, htmlEncode(colorValue)); // colorValue may be a cart override, escape (XSS)
 printf("&nbsp;<input id='%s_picker' />\n", varName);
 jsInlineF(
     "(function() {\n"
     "  var textEl = document.getElementById('%s_text');\n"
     "  var pickerEl = document.getElementById('%s_picker');\n"
     "  var checkEl = document.querySelector('input[type=checkbox][name=\"%s\"]');\n"
     "  $(pickerEl).spectrum({\n"
     "    color: textEl.value,\n"
     "    showPalette: true,\n"
     "    showSelectionPalette: true,\n"
     "    showInitial:true,\n"
     "    showInput: true,\n"
     "    preferredFormat: 'hex',\n"
     "    hideAfterPaletteSelect: true,\n"
     "    change: function(color) { textEl.value = color.toHexString(); checkEl.checked = true; }\n"