diff --git a/share/man/man4/bge.4 b/share/man/man4/bge.4
--- a/share/man/man4/bge.4
+++ b/share/man/man4/bge.4
@@ -29,7 +29,7 @@
 .\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
 .\" THE POSSIBILITY OF SUCH DAMAGE.
 .\"
-.Dd August 18, 2017
+.Dd January 16, 2026
 .Dt BGE 4
 .Os
 .Sh NAME
@@ -276,3 +276,11 @@
 while the system is up as the kernel is currently unable to cope with a
 .Nm
 interface disappearing.
+.Pp
+The UDP transmit checksum offloading is disabled by default, see
+.Va dev.bge.%d.forced_udpcsum .
+To avoid problems when the interface is a member of a
+.Xr bridge 4
+interface, all transmit checksum offloading is initially disabled in this case.
+Transmit checksum offloading can be enabled using
+.Xr ifconfig 8 .
diff --git a/sys/dev/bge/if_bge.c b/sys/dev/bge/if_bge.c
--- a/sys/dev/bge/if_bge.c
+++ b/sys/dev/bge/if_bge.c
@@ -3721,7 +3721,12 @@
 	if_setgetcounterfn(ifp, bge_get_counter);
 	if_setsendqlen(ifp, BGE_TX_RING_CNT - 1);
 	if_setsendqready(ifp);
-	if_sethwassist(ifp, sc->bge_csum_features);
+	/* Initially enable checksum offloading either for all of IPv4, TCP/IPv4
+	 * and UDP/IPv4, or for none. This avoids problems when the interface
+	 * is added to a bridge.
+	 */
+	if (sc->bge_csum_features & CSUM_UDP)
+		if_sethwassist(ifp, sc->bge_csum_features);
 	if_setcapabilities(ifp, IFCAP_HWCSUM | IFCAP_VLAN_HWTAGGING |
 	    IFCAP_VLAN_MTU);
 	if ((sc->bge_flags & (BGE_FLAG_TSO | BGE_FLAG_TSO3)) != 0) {
@@ -3732,6 +3737,13 @@
 	if_setcapabilitiesbit(ifp, IFCAP_VLAN_HWCSUM, 0);
 #endif
 	if_setcapenable(ifp, if_getcapabilities(ifp));
+	/*
+	 * Disable TXCSUM capability initially, if UDP checksum offloading is
+	 * not enabled. This avoids problems when the interface is added to a
+	 * bridge.
+	 */
+	if ((sc->bge_csum_features & CSUM_UDP) == 0)
+		if_setcapenablebit(ifp, 0, IFCAP_TXCSUM);
 #ifdef DEVICE_POLLING
 	if_setcapabilitiesbit(ifp, IFCAP_POLLING, 0);
 #endif