diff --git a/0001-Fix-allocated-memory-of-QByteArray.patch b/0001-Fix-allocated-memory-of-QByteArray.patch
new file mode 100644
index 0000000..66515be
--- /dev/null
+++ b/0001-Fix-allocated-memory-of-QByteArray.patch
@@ -0,0 +1,49 @@
+From 6485b6d45ad165cf976138cf8ab683c42515e794 Mon Sep 17 00:00:00 2001
+From: Kai Koehne <kai.koehne@qt.io>
+Date: Tue, 13 Oct 2020 15:47:31 +0200
+Subject: [PATCH] Fix allocated memory of QByteArray returned by QIODevice::readLine
+
+If the maxSize argument is 0 (the default), QIODevice::readLine will
+allocate a QByteArray with the size of the next chunk of data, which
+may be quite large. Before returning, it then resizes the byte array
+to the actual size that was read.
+
+But since change 6b884d2aa129, QByteArray::resize() does no
+longer shrink the capacity. This means that the returned QByteArray
+keeps it's maximum size as allocated memory. This can lead to
+excessive memory consumption, especially if the returned QByteArray's
+are stored for further processing in the client code.
+
+Fix this by explicitly calling QByteArray::squeeze() before returning.
+
+[ChangeLog][QtCore][QIODevice] Fixes a regression in Qt 5.15 causing
+QByteArray's that are returned by QIODevice::readLine() to
+consume large amounts of memory.
+
+Fixes: QTBUG-87010
+Change-Id: I1f95fc4098849e900680fc945238bfeda881022c
+Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
+(cherry picked from commit 263b29eedb223dec1ecaee193302070af87a1852,
+limited squeeze() call if bytes are actually read to preserve retVal.isNull()
+behavior in 5.15)
+---
+
+diff --git a/src/corelib/io/qiodevice.cpp b/src/corelib/io/qiodevice.cpp
+index cc1d110..0f11c2e 100644
+--- a/src/corelib/io/qiodevice.cpp
++++ b/src/corelib/io/qiodevice.cpp
+@@ -1480,10 +1480,12 @@
+     } else
+         readBytes = readLine(result.data(), result.size());
+ 
+-    if (readBytes <= 0)
++    if (readBytes <= 0) {
+         result.clear();
+-    else
++    } else {
+         result.resize(readBytes);
++        result.squeeze();
++    }
+ 
+     return result;
+ }
diff --git a/libqt5-qtbase.changes b/libqt5-qtbase.changes
index ac9add5..15cb341 100644
--- a/libqt5-qtbase.changes
+++ b/libqt5-qtbase.changes
@@ -1,3 +1,9 @@
+-------------------------------------------------------------------
+Tue Dec 29 11:48:35 UTC 2020 - Arjen de Korte <suse+build@de-korte.org>
+
+- Add patch to avoid excessive use of memory by lconvert:
+  * 0001-Fix-allocated-memory-of-QByteArray.patch
+
 -------------------------------------------------------------------
 Fri Nov 20 12:08:44 UTC 2020 - Fabian Vogt <fabian@ritter-vogt.de>
 
diff --git a/libqt5-qtbase.spec b/libqt5-qtbase.spec
index abd0e57..75a754d 100644
--- a/libqt5-qtbase.spec
+++ b/libqt5-qtbase.spec
@@ -70,6 +70,8 @@ Patch12:        0001-Add-remote-print-queue-support.patch
 Patch21:        0001-Don-t-white-list-recent-Mesa-versions-for-multithrea.patch
 Patch24:        fix-fixqt4headers.patch
 # patches 1000-2000 and above from upstream 5.15 branch #
+# Merged: https://bugreports.qt.io/browse/QTBUG-87010
+Patch1000:      0001-Fix-allocated-memory-of-QByteArray.patch
 # patches 2000-3000 and above from upstream qt6/dev branch #
 # Not accepted yet, https://codereview.qt-project.org/c/qt/qtbase/+/255384
 Patch2001:      0002-Synthesize-Enter-LeaveEvent-for-accepted-QTabletEven.patch