diff --git a/copyparty/broker_mp.py b/copyparty/broker_mp.py
index 52c9afed..b1b2f9d9 100644
--- a/copyparty/broker_mp.py
+++ b/copyparty/broker_mp.py
@@ -157,6 +157,10 @@ class BrokerMp(object):
         elif dest == "cb_httpsrv_up":
             self.hub.cb_httpsrv_up()
 
+        elif dest == "httpsrv.set_bad_ver":
+            for p in self.procs:
+                p.q_pend.put((0, dest, list(args)))
+
         else:
             raise Exception("what is " + str(dest))
 
diff --git a/copyparty/broker_thr.py b/copyparty/broker_thr.py
index 43bea239..b433a300 100644
--- a/copyparty/broker_thr.py
+++ b/copyparty/broker_thr.py
@@ -61,6 +61,10 @@ class BrokerThr(BrokerCli):
             self.httpsrv.set_netdevs(args[0])
             return
 
+        if dest == "httpsrv.set_bad_ver":
+            self.httpsrv.set_bad_ver(args[0])
+            return
+
         # new ipc invoking managed service in hub
         obj = self.hub
         for node in dest.split("."):
diff --git a/copyparty/httpcli.py b/copyparty/httpcli.py
index 472c270c..0be15e56 100644
--- a/copyparty/httpcli.py
+++ b/copyparty/httpcli.py
@@ -155,7 +155,8 @@ ALL_COOKIES = "k304 no304 js idxh dots cppwd cppws".split()
 BADXFF = " due to dangerous misconfiguration (the http-header specified by --xff-hdr was received from an untrusted reverse-proxy)"
 BADXFF2 = ". Some copyparty features are now disabled as a safety measure.\n\n\n"
 BADXFP = ', or change the copyparty global-option "xf-proto" to another header-name to read this value from. Alternatively, if your reverseproxy is not able to provide a header similar to "X-Forwarded-Proto", then you must tell copyparty which protocol to assume; either "--xf-proto-fb=http" or "--xf-proto-fb=https"'
-BADXFFB = "<b>NOTE: serverlog has a message regarding your reverse-proxy config</b>"
+BADXFFB = "<div class='box-warning'>NOTE: serverlog has a message regarding your reverse-proxy config</div>"
+BADVER = "<div class='box-warning'>The version of copyparty currently active has a known vulnerability <a class='unbox' href='https://github.com/9001/copyparty/security'>(more info)</a> that has been fixed; please update to the latest version. This message is only visible to users with admin (a/A) permissions.</div>"
 
 H_CONN_KEEPALIVE = "Connection: Keep-Alive"
 H_CONN_CLOSE = "Connection: Close"
@@ -5624,7 +5625,8 @@ class HttpCli(object):
             no304=self.no304(),
             k304vis=self.args.k304 > 0,
             no304vis=self.args.no304 > 0,
-            msg=BADXFFB if hasattr(self, "bad_xff") else "",
+            msg=(BADXFFB if not hasattr(self, "bad_xff") else "")
+            + (BADVER if self.conn.hsrv.bad_ver and self.can_admin else ""),
             ver=S_VERSION if show_ver else "",
             chpw=self.args.chpw and self.uname != "*",
             ahttps="" if self.is_https else "https://" + self.host + self.req,
diff --git a/copyparty/httpsrv.py b/copyparty/httpsrv.py
index ea89a0aa..728a3743 100644
--- a/copyparty/httpsrv.py
+++ b/copyparty/httpsrv.py
@@ -119,6 +119,7 @@ class HttpSrv(object):
         socket.setdefaulttimeout(120)
 
         self.t0 = time.time()
+        self.bad_ver = False
         nsuf = "-n{}-i{:x}".format(nid, os.getpid()) if nid else ""
         self.magician = Magician()
         self.nm = NetMap([], [])
@@ -232,6 +233,9 @@ class HttpSrv(object):
         self.th_cfg: dict[str, set[str]] = {}
         Daemon(self.post_init, "hsrv-init2")
 
+    def set_bad_ver(self, val: bool) -> None:
+        self.bad_ver = val
+
     def post_init(self) -> None:
         try:
             x = self.broker.ask("thumbsrv.getcfg")
diff --git a/copyparty/svchub.py b/copyparty/svchub.py
index 929392f7..f17c502d 100644
--- a/copyparty/svchub.py
+++ b/copyparty/svchub.py
@@ -4,6 +4,7 @@ from __future__ import print_function, unicode_literals
 import argparse
 import atexit
 import errno
+import json
 import logging
 import os
 import re
@@ -27,6 +28,7 @@ if True:  # pylint: disable=using-constant-test
     from typing import Any, Optional, Union
 
 from .__init__ import ANYWIN, EXE, MACOS, PY2, TYPE_CHECKING, E, EnvParams, unicode
+from .__version__ import S_VERSION
 from .authsrv import BAD_CFG, AuthSrv, derive_args, n_du_who, n_ver_who
 from .bos import bos
 from .cert import ensure_cert
@@ -75,6 +77,7 @@ from .util import (
     mp,
     odfusion,
     pybin,
+    read_utf8,
     start_log_thrs,
     start_stackmon,
     termsize,
@@ -95,11 +98,19 @@ if TYPE_CHECKING:
 if PY2:
     range = xrange  # type: ignore
 
+if PY2:
+    from urllib2 import Request, urlopen
+else:
+    from urllib.request import Request, urlopen
+
 
 VER_IDP_DB = 1
 VER_SESSION_DB = 1
 VER_SHARES_DB = 2
 
+VULN_CHECK_URL = "https://api.github.com/repos/9001/copyparty/security-advisories"
+VULN_CHECK_INTERVAL = 86400
+
 
 class SvcHub(object):
     """
@@ -1382,6 +1393,7 @@ class SvcHub(object):
             Daemon(self.tcpsrv.netmon, "netmon")
 
         Daemon(self.thr_httpsrv_up, "sig-hsrv-up2")
+        Daemon(self.check_ver, "ver-chk")
 
         sigs = [signal.SIGINT, signal.SIGTERM]
         if not ANYWIN:
@@ -1778,3 +1790,61 @@ class SvcHub(object):
         zb = gzip.compress(zb)
         zs = ub64enc(zb).decode("ascii")
         self.log("stacks", zs)
+
+    def parse_version(self, ver: str) -> tuple:
+        match = re.search(r'[\d.]+', ver)
+        if not match:
+            return ()
+        clean = match.group(0).strip('.')
+        return tuple(int(x) for x in clean.split("."))
+
+    def get_vuln_cache_path(self) -> str:
+        return os.path.join(self.E.cfg, "vuln_advisory.json")
+
+    def check_ver(self) -> None:
+        ver_cpp = self.parse_version(S_VERSION)
+
+        while not self.stopping:
+            fpath = self.get_vuln_cache_path()
+            data = None
+
+            try:
+                mtime = os.path.getmtime(fpath)
+                if time.time() - mtime < VULN_CHECK_INTERVAL:
+                    data = read_utf8(None, fpath, True)
+            except Exception as e:
+                self.log("ver-chk", "no vulnerability advisory cache found; {}".format(e))
+
+            if not data:
+                try:
+                    req = Request(VULN_CHECK_URL)
+                    with urlopen(req, timeout=30) as f:
+                        data = f.read().decode("utf-8")
+
+                    with open(fpath, "wb") as f:
+                        f.write(data.encode("utf-8"))
+
+                except Exception as e:
+                    self.log("ver-chk", "failed to fetch vulnerability advisory; {}".format(e))
+
+            if data:
+                try:
+                    advisories = json.loads(data)
+                    
+                    fixes = (
+                        self.parse_version(vuln.get("patched_versions"))
+                        for adv in advisories
+                        for vuln in adv.get("vulnerabilities", [])
+                        if vuln.get("patched_versions")
+                    )
+                    newest_fix = max(fixes, default=None)
+
+                    if newest_fix and ver_cpp < newest_fix:
+                        self.broker.say("httpsrv.set_bad_ver", True)
+                except Exception as e:
+                    self.log("ver-chk", "failed to process vulnerability advisory; {}".format(e))
+
+            for _ in range(VULN_CHECK_INTERVAL):
+                if self.stopping:
+                    return
+                time.sleep(1)
diff --git a/copyparty/web/splash.css b/copyparty/web/splash.css
index 832ef566..5ddcd18f 100644
--- a/copyparty/web/splash.css
+++ b/copyparty/web/splash.css
@@ -257,3 +257,19 @@ html.bz {
 html.bz .vols img {
 	filter: sepia(0.8) hue-rotate(180deg);
 }
+.box-warning {
+	background: #804;
+	border-bottom: 1px solid #c28;
+	padding: .75em;
+	text-align: center;
+	border-radius: .2em;
+	margin-top: 0em;
+}
+.box-warning + .box-warning {
+	margin-top: .5em;
+}
+.unbox {
+	border: unset !important;
+	padding: unset !important;
+	margin: unset !important;
+}
\ No newline at end of file