diff --git a/include/znc/IRCSock.h b/include/znc/IRCSock.h
index 73a1b550..4852a2e8 100644
--- a/include/znc/IRCSock.h
+++ b/include/znc/IRCSock.h
@@ -171,6 +171,8 @@ class CIRCSock : public CIRCSocket {
     // TODO move this function to CIRCNetwork and make it non-static?
     static bool IsFloodProtected(double fRate);
 
+    bool IsNickVisibleInAttachedChannels(const CString& sNick) const;
+
   private:
     // Message Handlers
     bool OnAccountMessage(CMessage& Message);
diff --git a/src/IRCSock.cpp b/src/IRCSock.cpp
index b9ce227c..a349ca56 100644
--- a/src/IRCSock.cpp
+++ b/src/IRCSock.cpp
@@ -322,8 +322,25 @@ static void FixupChanNick(CNick& Nick, CChan* pChan) {
     }
 }
 
+// #1826: CAP away-notify clients shouldn't receive notifications if all shared
+// channels are detached
+// This applies to account, away-notify, and chghost.
+bool CIRCSock::IsNickVisibleInAttachedChannels(const CString& sNick) const {
+    const vector<CChan*>& vChans = m_pNetwork->GetChans();
+    for (const CChan* pChan : vChans) {
+        if (!pChan->IsDetached() && pChan->FindNick(sNick)) {
+            return true;
+        }
+    }
+    return false;
+}
+
 bool CIRCSock::OnAccountMessage(CMessage& Message) {
     // TODO: IRCSOCKMODULECALL(OnAccountMessage(Message)) ?
+    // Do not send ACCOUNT if all shared channels are detached.
+    if (!IsNickVisibleInAttachedChannels(Message.GetNick().GetNick())) {
+        return true;
+    }
     return false;
 }
 
@@ -377,6 +394,10 @@ bool CIRCSock::OnActionMessage(CActionMessage& Message) {
 
 bool CIRCSock::OnAwayMessage(CMessage& Message) {
     // TODO: IRCSOCKMODULECALL(OnAwayMessage(Message)) ?
+    // Do not send away-notify if all shared channels are detached.
+    if (!IsNickVisibleInAttachedChannels(Message.GetNick().GetNick())) {
+        return true;
+    }
     return false;
 }
 
@@ -570,6 +591,10 @@ bool CIRCSock::OnCTCPMessage(CCTCPMessage& Message) {
 }
 
 bool CIRCSock::OnChgHostMessage(CChgHostMessage& Message) {
+    // Do not send chghost if all shared channels are detached.
+    if (!IsNickVisibleInAttachedChannels(Message.GetNick().GetNick())) {
+        return true;
+    }
     // The emulation of QUIT+JOIN would be cleaner inside CClient::PutClient()
     // but computation of new modes is difficult enough so that I don't want to
     // repeat it for every client
diff --git a/test/integration/tests/core.cpp b/test/integration/tests/core.cpp
index 0a56ba72..197ea6d3 100644
--- a/test/integration/tests/core.cpp
+++ b/test/integration/tests/core.cpp
@@ -1221,5 +1221,58 @@ TEST_F(ZNCTest, DisconnectedTagmsgCrash) {
     client.ReadUntil("AddServer");
 }
 
+// https://github.com/znc/znc/issues/1826
+TEST_F(ZNCTest, CAPDetached) {
+    auto znc = Run();
+    auto ircd = ConnectIRCd();
+
+    ircd.Write("CAP user LS :away-notify");
+    ircd.ReadUntil("CAP REQ :away-notify");
+    ircd.Write("CAP user ACK :away-notify");
+
+    ircd.Write("CAP user LS :chghost");
+    ircd.ReadUntil("CAP REQ :chghost");
+    ircd.Write("CAP user ACK :chghost");
+
+    ircd.Write("CAP user LS :account-notify");
+    ircd.ReadUntil("CAP REQ :account-notify");
+    ircd.Write("CAP user ACK :account-notify");
+
+    auto client = LoginClient();
+
+    client.Write("CAP LS");
+
+    client.Write("CAP REQ :cap-notify");
+    client.ReadUntil("ACK :cap-notify");
+    client.Write("CAP REQ :away-notify");
+    client.ReadUntil("ACK :away-notify");
+    client.Write("CAP REQ :chghost");
+    client.ReadUntil("ACK :chghost");
+    client.Write("CAP REQ :account-notify");
+    client.ReadUntil("ACK :account-notify");
+    client.Write("CAP END");
+
+    client.Write(":nick!ident@host JOIN #test");
+    ircd.Write(":test!test@test JOIN #test");
+    client.ReadUntil(":test!test@test JOIN #test");
+    ircd.Write("353 nick = #test :nick!ident@host test!test@test");
+    ircd.Write("366 nick #test :End of /NAMES list.");
+    client.ReadUntil("#test :End of /NAMES");
+    client.Write("znc detach #test");
+    client.ReadUntil(":*status!status@znc.in PRIVMSG nick :Detached 1 channel");
+
+    ircd.Write(":test!test@test ACCOUNT test");
+    EXPECT_THAT(client.ReadRemainder().toStdString(), Not(HasSubstr(":test!test@test ACCOUNT test")))
+        << "Client saw account-notify even though all channels are detached";
+
+    ircd.Write(":test!test@test AWAY :going away");
+    EXPECT_THAT(client.ReadRemainder().toStdString(), Not(HasSubstr(":test!test@test AWAY :going away")))
+        << "Client saw away-notify even though all channels are detached";
+
+    ircd.Write(":test!test@test CHGHOST test detached.test");
+    EXPECT_THAT(client.ReadRemainder().toStdString(), Not(HasSubstr(":test!test@test CHGHOST test detached.test")))
+        << "Client saw chghost even though all channels are detached";
+}
+
 }  // namespace
 }  // namespace znc_inttest