diff --git a/.gitignore b/.gitignore
index 47df368..a732df8 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,5 +2,5 @@ SOURCES/cbindgen-vendor.tar.xz
 SOURCES/nspr-4.36.0-2.el8_2.src.rpm
 SOURCES/nss-3.112.0-1.el9_4.src.rpm
 SOURCES/nss-3.112.0-4.el8_2.src.rpm
-SOURCES/thunderbird-140.9.0esr.processed-source.tar.xz
-SOURCES/thunderbird-langpacks-140.9.0esr-20260323.tar.xz
+SOURCES/thunderbird-140.9.1esr.processed-source.tar.xz
+SOURCES/thunderbird-langpacks-140.9.1esr-20260409.tar.xz
diff --git a/.thunderbird.metadata b/.thunderbird.metadata
index ee9a524..a16c265 100644
--- a/.thunderbird.metadata
+++ b/.thunderbird.metadata
@@ -2,5 +2,5 @@ bc4adac8f38f5103d8f88564a1545063dd8d6402 SOURCES/cbindgen-vendor.tar.xz
 0d0ddbd2a73340b3cbc977997f57222946b1e775 SOURCES/nspr-4.36.0-2.el8_2.src.rpm
 fd3879b176634d66f8ef64d18fdaeec98e140c23 SOURCES/nss-3.112.0-1.el9_4.src.rpm
 c3f0aaef37972107442e2796efad71be3a98ce3c SOURCES/nss-3.112.0-4.el8_2.src.rpm
-2ae7c10369b0d0148d557655739fac8b0bf3073b SOURCES/thunderbird-140.9.0esr.processed-source.tar.xz
-b819d4304c941d72656c004c4887cc7709185380 SOURCES/thunderbird-langpacks-140.9.0esr-20260323.tar.xz
+75159f7d43bf4d117955ddaec4d0d4f4b1c2e07e SOURCES/thunderbird-140.9.1esr.processed-source.tar.xz
+4a4768adaedeb986823ce7c215ab28c8f672c8a8 SOURCES/thunderbird-langpacks-140.9.1esr-20260409.tar.xz
diff --git a/SOURCES/exceptionHandled-for-IO-error-processhandler.patch b/SOURCES/exceptionHandled-for-IO-error-processhandler.patch
new file mode 100644
index 0000000..e6267a5
--- /dev/null
+++ b/SOURCES/exceptionHandled-for-IO-error-processhandler.patch
@@ -0,0 +1,29 @@
+diff -up firefox-140.1.0/testing/mozbase/mozprocess/mozprocess/processhandler.py.exceptionHandled-for-IO-error-processhandler firefox-140.1.0/testing/mozbase/mozprocess/mozprocess/processhandler.py
+--- firefox-140.1.0/testing/mozbase/mozprocess/mozprocess/processhandler.py.exceptionHandled-for-IO-error-processhandler	2025-07-14 19:14:55.000000000 +0200
++++ firefox-140.1.0/testing/mozbase/mozprocess/mozprocess/processhandler.py	2025-08-05 18:05:54.329479764 +0200
+@@ -1098,11 +1098,22 @@ class ProcessReader:
+ 
+     def _read_stream(self, stream, queue, callback):
+         sentinel = "" if isinstance(stream, io.TextIOBase) else b""
+-        for line in iter(stream.readline, sentinel):
+-            queue.put((line, callback))
++        try:
++            for line in iter(stream.readline, sentinel):
++                queue.put((line, callback))
++        except ValueError as e:
++            if "I/O operation on closed file" in str(e):
++                # Stream was closed by the process, this is normal
++                pass
++            else:
++                raise
+         # Give a chance to the reading loop to exit without a timeout.
+         queue.put((b"", None))
+-        stream.close()
++        try:
++            stream.close()
++        except ValueError:
++            # Stream might already be closed
++            pass
+ 
+     def start(self, proc):
+         queue = Queue()
diff --git a/SPECS/thunderbird.spec b/SPECS/thunderbird.spec
index eb2d87e..b7d2559 100644
--- a/SPECS/thunderbird.spec
+++ b/SPECS/thunderbird.spec
@@ -137,7 +137,7 @@ end}
 
 Summary:        Mozilla Thunderbird mail/newsgroup client
 Name:           thunderbird
-Version:        140.9.0
+Version:        140.9.1
 Release:        1%{?dist}
 URL:            http://www.mozilla.org/projects/thunderbird/
 License:        MPLv1.1 or GPLv2+ or LGPLv2+
@@ -165,7 +165,7 @@ ExcludeArch:    %{ix86}
 #Source0:        https://archive.mozilla.org/pub/thunderbird/releases/%%{version}%%{?pre_version}/source/thunderbird-%%{version}%%{?pre_version}.processed-source.tar.xz
 Source0:        thunderbird-%{version}%{?pre_version}%{?buildnum}.processed-source.tar.xz
 %if %{with langpacks}
-Source1:        thunderbird-langpacks-%{version}%{?pre_version}-20260323.tar.xz
+Source1:        thunderbird-langpacks-%{version}%{?pre_version}-20260409.tar.xz
 %endif
 Source2:        cbindgen-vendor.tar.xz
 Source3:        process-official-tarball
@@ -205,6 +205,8 @@ Patch19:        build-min-lexical.patch
 
 # -- Upstreamed patches --
 Patch51:       mozilla-bmo1170092.patch
+Patch52:       exceptionHandled-for-IO-error-processhandler.patch
+
 
 # -- Submitted upstream, not merged --
 Patch102:       mozilla-bmo1670333.patch
@@ -1107,6 +1109,7 @@ echo "--------------------------------------------"
 
 # -- Upstreamed patches --
 %patch -P51 -p1 -b .mozilla-bmo1170092
+%patch -P52 -p1 -b .exceptionHandled-for-IO-error-processhandler
 
 # -- Submitted upstream, not merged --
 %patch -P102 -p1 -b .mozilla-bmo1670333
@@ -1717,6 +1720,9 @@ gtk-update-icon-cache %{_datadir}/icons/hicolor &>/dev/null || :
 #===============================================================================
 
 %changelog
+* Thu Apr  9 2026 Jan Horak <jhorak@redhat.com> - 140.9.1-1
+- Update to 140.9.1 ESR
+
 * Mon Mar 23 2026 Jan Horak <jhorak@redhat.com> - 140.9.0-1
 - Update to 140.9.0 ESR